kind, whether old or new. The old are simply in
it ignored or not employed, and of new there are
none. This it is that makes the office of the
civil engineer a very curious and interesting one,
and one well worth a few thoughts and a little
inquiry. Can it be helped in any way, and from
what source?

artistic forms have always been peculiar to the
nation and time which employed them, and
peculiar to that nation and that time only.
Thus, to take one instance by way of making
our meaning clear, and to prepare the way
for the better understanding of what is to
follow, the old Egyptians needed houses to live
in and temples to worship in, and after having
But before we proceed it is absolutely necessary
provided themselves in the most matter-of-fact to note one other element in modern civil engi-
way with the necessary buildings, the four walls neering, and one which is almost as remarkable
and roofing, they always had ready the most as either of the two things or systems of doing
ample stock of " ornaments and architecture work we have named; it is where the civil engi-
and fine art with which to clothe this necessary Leer has himself borrowed more or less from the
and simply useful constructional building. But past and fitted what he has borrowed into or on to
it must be observed that all their ornaments and his simple constructive work, or, in other and
fine art were their own and unborrowed, and got more practical words, where he has been assisted
primarily from the plants and animals of the by the architectural draughtsman, or even some-
country, and fitted for their purposes by the act times by the artist. To exemplify this there is no
of passing through their minds, and the being better work than the ingenious lattice girder
worked out by Egyptian hands, and thus made bridge by Mr. Hawkshaw over the Thames at
peculiar to and characteristic of themselves, their Hungerford Market. This bridge, as is so well
country, and the age in which they lived. And known, has what are termed "architectural fea-
thus it was of all the great primitive architectures tures "tacked on to it, that is, after all the engi-
and fine arts of past times. All the great unbor-neering and necessary constructive work had been
rowed styles of art and architecture have been done, and the bridge fit for use, the architect has
thus records of the science and art, the arts, too, been called in to fix on to it some architectural or
of peace and war, and the costume of the times ornamental adjuncts, adding nothing in any way
in which they severally prevailed. But in the to the constructional requirements of the structure,
present day all this is nearly or quite reversed. but simply intended, as it is thought, to ornament
Instead of the primitive simplicity and originality it. The Lambeth Bridge is, as we have noted,
always to be found in antique buildings, i.e., the pure constructive engineering, the Hungerford
necessary constructional requirements and forms Bridge is also pure constructive engineering, but
ornamented, it is but too commonly the case that with the addition afterwards of "architecture."
the very building and the constructional and ne- The result is alike lamentable and absurd enough,
cessary arrangements of it are borrowed either e.g., five lamps, which are never lighted, over a
wholly or in part from some older structure, as mass of stonework which has nothing to do with
in church architecture, and then on and over this the necessary supportings of the structure. But
borrowed construction, borrowed ornament, from this, by the way; we adduce this bridge simply
some distant country or age is added and literally by way of illustration, and as showing a principle
tacked on to it. This is the almost universal at work in modern doings. One more example
system of doing things in these modern days, in- will make it yet clearer-the new Blackfriars
deed, it is the fine art and architecture of the Bridge, by Mr. Cubitt. Nothing can be simpler
nineteenth century, and the only exception to it and more evident than the mere constructional
is, and it is this fact that must make it interesting necessities of this bridge, with its five wide arches
to all mechanical readers, the works of pure civil and their supporting piers, and had this mere con-
engineering-that is, those works wherein no struction been left in its bare and simply useful
effort has been made to add to the mere and state it would have added another example to
simple and necessary construction any borrowed those we have already cited of purely engineering
fine art or architectural feature. As an instance works. But in it the architect, or rather the
of this, and it is a curious one, and worth note, architectural draughtsman, has been called in not
the Lambeth Suspension Bridge may be adduced. so much to ornament the construction as to almost
No attempt whatever has been made by the engi-hide it altogether, and to fix the ornament on to
neer of this bridge to ornament the constructional it, and which has been done literally. The elabo-
forms. The whole work is as purely practical as
a steam engine boiler; indeed, the very piers
themselves, over which the suspension chains pass,
are of sheet iron, and put together in the same
way as an ordinary boiler. The chains, as might
be expected, are purely constructive without any
attempt at ornament, and the very hand-railing is
a simple trellis. It is among the few things in
London wherein may be seen the work of the
constructional engineer altogether uninfluenced
by the art, as it is termed, of the time. It is a
work of pure engineering and nothing more, and
has always seemed to us, consequently, a very in-
teresting work. The railway bridge over the Black-
friars-road is another work of this kind, wherein
nothing but the purely engineering and construc-
tive element is visible, no attempt having been
made to ornament, or to add to it, after its build-
ing any architectural form, even in outline,
borrowed from the past. Now there is, and always
must be, interest in works of this kind, because
we see in them the results of some problem of
pure necessity; given the work to be done, and
these things show how it may be done, and with
what means, whether few or many, simple or
complicated, and we see, too, the whole mind of
the man who did the work and his only. It may
very well be doubted whether it be possible to
find in modern doing things so entirely and purely
modern and of to-day, as are these railway and
river works. There was no "precedent" to go
to and borrow from, so that those who contrived
them were left entirely to their own and modern a crypt the whole building would have tumbled to
mechanical resources and ways of putting mate-
rials together. They are not ornamented, and for
this simple reason, and it is this which we would
call especially our readers' attention to, that there
was no modern idea of ornament to go to and

borrow from!

Thus we see that there are two distinct phases in modern building and construction; first, the borrowing ornament and even constructional forms and arrangements from the past and from other countries; and, secondly, there is this pure engineering, or the building up of necessary forms without the addition of ornaments at all or of any

rately carved capitals with their supporting
columns and carved bases, have nothing whatever
to do with the necessary construction of the
bridge, they do not help it in any way either in
reality or in appearance, and are, indeed, simply
tacked or fixed on to it after the bridge had been
completed as a thing of utility. Nothing ever
was more awkward, or more essentially modern.
We say nothing of the character of the caps and
columns, more fitted for a cathedral crypt, from
which they would seem to have been copied, than
as parts, ornamental parts, of a river bridge. We
only adduce it as an extreme example of modern
art and architecture as applied to engineering,
and to show how different are the ways of these
days in such matters than were those of gone-by
days, wherein, as in this case, these very columns,
had they been used at all, would at least have
been made to support the footway of the bridge,
and so had a special and quite necessary use, and
that use would have been evident to plain eye-
sight.

Thus do we see that the modern engineer and
the structures which he builds are altogether
different from the ways and buildings of other
and bygone days. The engineering and construc-
tion and the architecture and ornament of the
past were as one, and mutually helped and assisted
each other and went together. The ornament was
simply the construction cut into shape. Had you
in old days taken away a column from a church or

difficulties and conquering them, not by borrowing but out of their own resources. To the student of engineering this must be a subject of special interest, for most sure it is that there never was a time wherein there was a wider field for something better. Our own impression is that the great art of the future must grow out of pure construction and engineering, for every day adds to the proofs that old things are fast passing away, and that we in these days are but passing through a kind of transitional epoch, an interregnum of art, wherein efforts are made to borrow from the past the forms and shadows of the past without the ability to fully comprehend that past, or to understand the meaning of what it has left us. It is no wonder that none like to part with it, for at present there is nothing else but it, nothing to put in its place, but it surely does not follow that there never can be or will be anything else. May there not be even something in the future better and higher, though not truer ?

"

WHA

THAT to eat, drink, and avoid," stared us in the face at every corner of the London streets a few years back, but very few of us knew how to distinguish good and wholesome food, whether of a solid or of a liquid character, from that brief advice or from its answer "Take Culverwell's baths." Nothing further was told us and we were left in the dark as to defining what we should eat or what we should avoid, but as regards the drink, the instructions were definite, "Take Culverwell's baths." We are not aware whether the baths were intended to be taken inwardly, or for outward application only; be that as it may, there is no doubt as to the efficiency of a good bath to the human body towards ensuring and retaining good health. The instructions as to what we are to eat and avoid have been left for others to enforce upon us, at a later period, and these will be found in the monthly numbers of the "Food Journal," published by Messrs. Johnson and Son, of Castlestreet, Holborn. The journal has only been in existence about twelve months, and has already obtained great popularity. This is not more than it deserves, for its articles are not only numerous and well selected, but they are written with care by gentlemen and professors of experience and who are well acquainted with the subject upon which they write. One of the chief features of the work is, that of reporting trials and experiments upon different articles of food with a view to ascertaining the amount of sustaining properties to human life contained in them and for the discovery of adulteration and foreign matters with which they are mixed by the manufacturer or by the dealer It also treats upon social and sanitary science as may be observed by the following particulars upon damp dwellings in the November issue:

There can be little doubt that damp is the most formidable enemy to health which our English climate harbours. We are not far enough north for piercing cold to be habitually or seriously dangorous. We are not far enough south to be subject to the fevers, malaria, and sunstroke of hotter climates. But the list of ills arising from the moisture of our climate is a long one; it embraces the most destructive forms of phthisis and rheumatism, and includes some ailments, such as coughs and colds, from which it is no exaggeration to say that not one in a thousand is exempt.

habits of life, ought to be specially designed to protect "Our dress and our dwelling, our food and our us against inclement weather and its consequences; and no doubt to some extent they are so, but not in anything like an adequate degree; and it is notorious that our houses especially stand in need of improvement in this respect. This might easily take place if public attention were sufficiently directed to the necessity for it, and a dry house became an object of constant demand; but so long as the persons who take houses will rest quite content with their being roomy, well arranged, and pleasant looking, without much thought as to so long will the majority of builders continue to whether they are likely to prove dry and healthy,— neglect precautions which cannot be observed without some expense, and attention to which does not, they find, add to the money value of the houses that they erect. The first step to improvement in the average English dwelling-house is to create, if possible, a state of public opinion such as would render a badly constructed house an un

fragments; but the whole series of columns,
capitals, bases, and all of the Blackfriars Bridge
might be taken down and carted, or rather barged,
and sound as ever, and nobody would ever know
away to-morrow, and the bridge would be as good
of it except he took a boat to look. It is for
these reasons that we think a few thoughts on
modern and old architecture and engineering may
prove useful, and may serve to point out what a
vital change in the whole system of doing things
is needful if we would really and in principle
follow in the footsteps of those who have gone be-
fore us, and who have left us such proofs of ever-marketable article.
ready and inventive skill and power of meeting

"Damp, when it enters a house," says Dr. F. R.

Smith, comes in at the roof, at the doors and windows, through the walls, from the ground, or through leakage of pipes. The entrance of damp through the roof itself is fortunately so unpleasantly conspicuous, owing to its staining the ceilings, that it is not long in being found out, and before repairs more or less complete are made. But for this, roofs would be more commonly untrustworthy than they are, and injury to health and life would oftener occur through their failure. Many roofs are, however, so constructed that, in times of great rain and of snow, an inundation is almost inevitable; and the situation of such houses as are near trees exposes them every autumn to the danger of overflows from gutters stopped up with dead leaves. Roofs, to remain dry, should be of sufficiently steep pitch for the nature of their covering; flat tiles requiring a steeper roof than 'pan tiles,' and these latter a steeper roof than slates. Whatever the covering the materials should be good and well secured. Roofs should be so arranged as to dispense, as far as possible, with gutters and flats occurring in the middle of the building, but should, if practicable, throw off the whole of their water to the sides. The points where they join walls, parapets, and chimneys are especially vulnerable, and should be especially protected, either by a lead flashing,' or by a cement fillet with a small projection formed to overhang it in the brickwork. It is essential that tiles or slates should overlap one another sufficiently, and that, if the covering is of metal (as lead, zinc, or copper), it should be so laid as to be free to expand or contract with change of temperature; and in exposed situations it is essential for tiles, and desirable for slates, to be bedded in mortar. This, however, must be so done as not to prevent there being a clear drip from one tile or slate on to another; otherwise the mortar will become saturated, and will conduct the water to the inside of the roof.

is widely different. The harm done is insidious; cohol, for instance, is portable, powerful, and ef-
it may go on long without being detected; and fectual, but it affects respiration and rusts every
when perceived it may be difficult to find out metallic object wherever it is disengaged. On
how the mischief arises, and almost an impossibility the other hand, the use of chloralum is attended
for even an experienced person to devise a remedy. by no annoyance whatever, the patient at the
It must be recollected that nearly all the ma- most experiencing the agreeable sensations of a
terials used in building are porous, and con- mild vapour bath, whilst perfect purification is
sequently absorbent of moisture; many of them ensured. The simple method now adopted of
are previously wet to an extent little suspected, fumigating a room by means of what is known as
and in not a few instances they are even hygro- a scent disperser can be applied to chloralum. By
metric. A driving wind and rain, in an exposed forcing a jet of steam air across the top of a ca-
situation, will blow through many kinds of stone pillary tube, which projects from a bottle contain-
walls, and certainly through any sort of brick ing the chloralum, every portion of a chamber
wall, if of moderate thickness and solid build; may be thoroughly purified without the presence
and a wall built with sea sand contains in its of suffocating or acrid gases, as in the case of
very mortar joints a material which has a con- muriatic acid, which is sometimes used. Wherever
stant tendency to absorb moisture. Further, chloralum adheres it has a tendency to attract
many a wall which can withstand the ordinary moisture, to imprison the baneful dust, arrest the
attacks of rain falling against it will give way delicate and dangerous microzymes which float
before a stream of water poured down upon it at a about the atmosphere, and thus its effects will be
given point; and it constantly happens that the more lasting than those of a gas possessing less
arrangement of our houses is such as to give adhesive and persistent properties. To sum up
opportunities for this to occur somewhere or the matter, we have in chloralum a strong pre-
other. Lastly, bad workmanship, or unskilled ventive of decomposition and a powerful arrester
use of materials, will make defective walls out of of it when it has commenced. It absorbs the
even good bricks and sound stone.
noxious gases resulting from putrefaction, as we
have recently had occasion to know, and it
destroys parasites and germs in alimentary and
other substances. It may be used alike for
medical purposes and for preserving food, and is,
in fact, the safest and most efficacious antiseptic
and disinfectant the labours of the chemist have as
yet given to the world.

"It is then of the first importance, if a house is to be dry, to know how far the materials with which we propose to build will turn water, and if we find we cannot rely upon them to do this, to understand how to remedy their defects; for the same bricks or stones which, built up in one way, will form but a damp wall, may often be made, by other modes of handling, to resist weather thoroughly."

CHLORALUM.

YHLORALUM is the name of a disinfectant

CHLORALUM ist been introduced to the public, think it well in conclusion to point out how very

We have referred to the absolute necessity that exists for destroying the disease germs, in order to prevent the spread of the disease. One of the most contagious diseases-scarlet fever-is now very prevalent in some parts, and we, therefore, and so unique is the compound in itself, and so readily the spread of disease and death is effected. remarkable are its properties, that we cannot fail And this we shall do on the authority of Dr. Bell, "When a roof is found to be defective, the fault to recognise in it one of the great scientific dis- of St. Andrew's, who has made some very careful is commonly due to broken or ill-secured slates or coveries of the day. As such it is well worthy of examinations into the subject. The facts were tiles, to defective covering to the joints next the a notice at our hands, the more so, perhaps, in stated by Professor Gamgee in a lecture on protecwalls, or to badly arranged gutters. In some that the discovery is due to a gentleman whose name tion from contagion, which he gave last week at cases it may be necessary to re-arrange the con- is well known in our pages as having made great Penrith. Let us first observe that a case of struction of the roofing, with a view to throw off strides in the art of arresting decay and in pre- contagious disease at its outset is scarcely conthe water more completely; but in the majority serving animal substances. We allude to Pro-tagious, whereas it is difficult to say when the conof instances the remedy is to replace bad materials fessor Gamgee, whose system of preserving meat valescent ceases to throw off an abundant mass of and workmanship with better ones. Where it is was fully described in the MECHANICS' MAGAZINE effective poison. The scarlet fever patient peels, admissible, a simply arranged and well confor the 25th of March last. For some time past and the material thrown off drops here and there, structed thatched roof is dry as well as warm. the Professor has prosecuted inquiries into the and spreads disease and death in all directions. "For the same reason which makes the defects efficacy of the chloride of aluminium as a disin- Dr. Bell's case is highly illustrative of this, and in a roof comparatively harmless, from our present fectant, and has made it the subject of exhaustive is most instructive as showing how insidiously point of view, defects in doors and windows, experiment. This substance, which he has named disease may be communicated. It appears that though certainly injurious, are not the worst of chloralum, is a salt, and for all practical purposes between the 9th of May and the end of July several faults; for leaky windows, like an unsound roof, it may be viewed as the analogue of common salt. cases of scarlet fever occurred among the servants occasion discomfort when it rains, and they are It is a hydrated chloride of aluminium, and has and students of a certain educational institution, therefore likely to be found out and remedied. the active properties of chlorine or of hydro- healthily situated, well built, airy, and isolated in Our sash window, the ordinary kind in use in chloric acid without any causticity, odour, or any position. At the end of July the students dispersed. England, is well contrived for keeping out rain; other hurtful property. Chloralum has a sweetish No fresh case occurred in the place (St. Andrew's) when well made of seasoned materials, a sash astringent or aluminous taste, and resembles as an till the 8th of August, when the servant in a family window is, without doubt, a perfectly weather- antiseptic the solution of chloride of zinc, which visiting the place, and who had only been there a tight contrivance; and even when badly made it has been extensively used, although its poisonous week, was seized with the disease. On the 9th, is superior to a bad casement. Where casements nature has led to serious accidents. But the great a nurse in another family of visitors sickened, and are employed, the most weather-tight construc- peculiarity of chloralum is that, although it is as she and five others in the same house were tion is that which is universal in France, although powerful as carbolic acid, it can be taken like attacked. Having accidentally heard that the boy rarely seen in England. In this arrangement the common salt. Indeed, medical men are now using who brought milk to the college, where the disease window is divided into two folding casements, or it largely, and it is an invaluable agent as a gargle first appeared, had "peeled off the skin," accordglass doors, meeting in the centre, and both in cases of sore throat, diphtheria, scarlet fever, ing to his own statement, at the time of the outopened or closed at the same time; the joint or whooping cough. Harmless as carbolic acid break, Dr. Bell ascertained the following facts:being made tight by the edge of one casement is generally supposed to be, we are aware of a On May the 1st, the wife of the farmer who supbeing rounded, and the corresponding edge of case in which two horses were much injured by a plied the milk returned from a visit to a place the companion one hollowed. There is, however, quantity of the liquid falling over them. It is where two deaths from scarlet fever had occurred, a preference in England, when casements are deadly to cats and other small animals, and re- and fell ill within a few days. She milked the used, for their closing against a frame; and here cently a child died from sitting on a log which cows. After a while, the boy, whose occupation it a clever arrangement of hollows and projections had been sprinkled with it. These are of course was, also, to milk the cows and to take the milk will effect a good deal in the way of hindering the avoidable accidents, but it must be admitted that to town, had the disease lightly, and in due time passage of moisture. A projecting fillet of wood an absolutely harmless disinfecting agent which" peeled." He continued all the time at his work. so arranged as to throw off the water which in can with impunity be washed over the body or wet weather drains down the face of doors and swallowed, must prove a great boon to all. windows, is an excellent precaution against the Professor Gamgee unquestionably directs a entrance of moisture; and, where a somewhat deadly blow at the root of the evil-he attacks expensive expedient can be adopted, the me- the germs of disease with this new disinfectant. chanical contrivance called a water bar' is often Disease germs are unclean and noxious things, and successful in keeping out the weather at external they have to be removed and absolutely destroyed. doors and casement windows. For the ordinary When a mass of putrid matter has been treated leaky joints which constantly have to be en- with chloralum its decomposition ends. Whenever countered in some rough and ready way, there is contagious or eruptive fevers, either in men or no packing better than a piece of india-rubber animals prevail, their extension may, under tubing, nailed up against the edge of the defec- prudent management, be restricted within very tive joint. The enemy, however, attacks us narrow limits by washing the body, immersion in openly when it comes in at the window or the baths, dipping clothing in hot solutions, purifying roof; and the shape in which it shows itself woodwork and all things capable of holding the that of a stain or a pool of water-is a palpable guide to the locality where the defect is, and often furnishes a clue to the mode of applying a remedy.

"Where moisture penetrates the walls, the case

deadly and microscopical particles which are so
minute and invisible as rarely to exceed one
twenty-thousandth part of an inch in diameter.
Gaseous or volatile antiseptics are much used and
recommended; sulphurous acid, condensed in al-

But now comes the interest of the case. On mak-
ing out a list of the houses in which scarlet fever
had showed itself in St. Andrew's, and asking the
dairy woman for a list of the houses which she
supplied with milk, with one exception there was
a perfect agreement in the lists. In every house
to which milk had been sent, scarlet fever had
occurred. The cases were twenty-six in all. The
attack of the members of the two families of
visitors is accounted for by the fact that, when
the college broke up at the end of July, the milk
thus made available for the use of other
customers was sent to the very houses in which
the visitors resided. We have thus an illustration
of the facility with which a deadly disease may be
spread over a whole neighbourhood without the
faintest suspicion as to whence it comes.
It is a
lesson for the times, and teaches that every pre-
caution ought to be enforced in cases of contagious
disease.

THE INSTITUTION OF CIVIL ENGINEERS.

THE following paper on a "Description of the Contract of the Thames Embankment," by Mr. T. D. Ridley, Assoc. Inst. C.E., was read and discussed at this, the first meeting of the session 1870-71, held on the 8th inst., Charles B. Vignoles, Esq., F.R.S., President, in the chair.

The contract upon which these cofferdams were used was let by the Metropolitan Board of Works, in January, 1864, to Mr. A. W. Ritson. It extended from the landing pier at Waterloo Bridge to the eastern end of the Temple Gardens, a length of 1,970ft. Mr. J. W. Bazalgette, M. Inst. C.E., was the engineer-in-chief, and Mr. Edmund Cooper, M. Inst. C.E., was the resident engineer; the author having charge of the works for the contractor.

|

Nos. 1 and 2, the walings only being a little stouter,
averaging 14in. square.

When the dams had served their purpose, it became necessary to clear them away, aud before the first constructed had been begun. completion of the whole series the removal of those The piles in

front of the ordinary wall were cut off at a level of 3ft. under low water mark, and those in front of the Temple Pier at a level of 7ft. under low water mark. The removal of the piles and puddle was effected in the following manner :

beef, and was allowed N.; dd 6. In Before No. 3 dam was completed, No. 4 dam was these and in all the dams, except No. 3, the inner row of piles was placed so as to coincide with the riverward face of the concrete in the foundation trench. The piles, walings, and bolts of these dams were similar to those in dams Nos. 2, and 3; but the shoring was of a different character. Across the breadth of the wall the struts were all horizontal, and abutted against walings of whole timbers bolted to pairs of piles, driven into the solid ground bebind the foundation of the wall. These coupled piles were placed at distances of 18ft. apart from centre to centre, and were further supported by three back struts to each pair, two of which were horizontal and one raking. These struts abutted against The breadth reclaimed from the river by this por- piles driven into the slope of the filling material, and tion of the embankment varied from 110ft. to 270ft.; backed up with rubble stones. From the lower the depth of water, when the tide was low, in waling to the bottom of the trench, or to the solid front of the wall averaged 2ft., aud the rise of tide ground, the space in all the dams was filled up with was 18ft. 6in. The borings showed the bed of the clay, or with a mixture of clay and gravel, to give river to consist of sand and gravel, resting upon the further stability to the dam, and to assist the lower London clay, at depths varying from 21-58ft. to bolts to resist the pressure of the puddle. Sluices of 27-10ft. under low water mark, whilst the founda- 44in. elm plank, and having hinged flaps, were intion of the wall was in all cases designed to be car-serted in each dam, through the piles and puddle at ried down to a depth of 14ft. under low water mark. the level of the lower waling. For dams Nos. 1 It devolved upon the contractor to design dams and 2, these sluices were 8in. by 8in., internal cross to the satisfaction of the engineer, who reserved to section. In the Temple Pier dam there were two himself the power to adopt either caissons or coffer- sluices, 3ft. high and 1ft. wide, and for each of dams. The author considered that dams of timber the other dams there was one sluice of similar and puddle would not only be cheaper, but could section. In the Temple Pier dam two iron also be more expeditiously constructed, than iron cylinders, 8ft. in diameter, were sunk to a depth caissons; and having succeeded in obtaining the of 4ft. below the lowest level of the foundation, engineer's sanction to one of the plans which he for pump wells, and in each of the other submitted, the work was begun. dams one such cylinder was sunk. The volume The Temple Pier was the most important work of water lifted out of the Temple Pier dam varied in the contract, and it was therefore requisite to lay from 620 gallons to 1,200 gallons a minute, accordits foundation dry as soon as possible. To effecting as a less or a greater area of the foundation this two short dams, one at each end of the pier, was exposed; but in all the other dams there was completely enclosing a short length of the river wall, much less water to be pumped. As soon as the were first begun. No. 1 was 111ft. 6in. long by 25ft. walls in any of the dams had been raised 6ft. above broad, inside measure, and No. 2 was of similar low-water mark, no further pumping was needed, breadth but a few feet longer. These dams con- as the water which gathered when the tide was high sisted of two rows of piles of whole timbers, averag- was passed through the sluices at low water. ing 13in. square, with a clear space of 6ft. for puddle. Murray's chain pumps were used in all cases, and The piles were from 40ft. to 48ft. in length, having were found to be very efficacious. cast-iron shoes 701b. in weight, and were driven 4ft. into the clay. Cast iron was used in preference to wrought iron for the shoes, as giving, at an equal cost, a much larger base for the timber to rest upon. Where the driving was difficult, shoes having castiron bases and wrought-iron straps were employed. The piles were secured by three rows of walings of whole timbers, 13in. to 14in. square, through which The quantities of material used in the dams were: and passing through the puddle space, at distances In the Temple Pier dam, timber 152 cubic feet; iron, ot 6ft. 6in. horizontally, were bolts 24in. in diameter 285lb.; and puddle, 9 cubic yards per lineal foot of in the lower waling and 2in. in diameter in the dam. In the other dams, timber 117 cubic feet; iron, middle and upper walings. Cast-iron washers, 9in. 2021b.; and puddle, 9 cubic yards per lineal foot of in diameter and 23in. thick, were used to distribute dam. The staging, from which the dredging was the pressure over a large surface of the walings. executed and the piles driven, consumed 19.6 cubic To avoid the difficulty of having to procure a num-feet of timber and 13lb. of iron per lineal foot. ber of long timbers, the piles were in a few cases Sissons' and White's steam pile drivers, and those only of the full length required, and the others, of Appleby Brothers, were used, in addition to after being driven, had lengthening pieces fixed to others, wrought by manual labour. The cost of them, so as to raise the dam to a height of 4ft. driving was a little under 4d. per foot of the above the high water line. Before proceeding with pile when the ground was dredged, but was much the construction of these two dams, the ground was higher where the ground was not dredged. The not dredged, but in all the dams subsequently preparation of the piles cost seven-eighths of a constructed, the sand and gravel were cleared off penny, and the fixing of the walings and shoring to the level of the clay before the piles were driven. 44d. per cubic foot, exclusive of the cost of fixing When the ground had not been dredged, great the tie-bolts. difficulty was experienced in driving the piles, and in the two dams in question one-sixth of the whole number pitched, having shown symptons of failure, were drawn. In all cases the piles so drawn were observed to have cast their shoes, and their lower extremities were usually bruised into a mass of tangled shreds. The failure generally occurred when the piles were passing through a bed of compact sand, resting upon coarse open gravel. Beneath the gravel, and resting upon the clay, was a layer of septaria, which offered a serious impediment to the passage of the piles; but when once the clay was reached, the driving was comparatively easy. The space between the piles was dredged to the level of the clay and filled with well tempered puddle. The transverse struts, of which there was a tier to each waling, were of whole timbers, 8ft. apart in the length of the dam.

Upon the tops of the piles of each side of the dam half beams were fixed, and upon these rails were laid so as to form a road, upon which the steam cranes and dredging machines to be used in the removal of the puddle could travel, and upon which the pile cutter could also be moved. These machines were successively placed in position, and the work was begun. For the first 15ft. in depth the puddle was filled into skips, and hoisted by means of steam cranes. Below that depth it was dredged by the machines which had been used for excavating the trench. When the puddle had been cleared away to the requisite depth, the pile-cutter followed and performed its part of the work. This machine consisted of a platform upon a stout frame, resting upon four wheels, which travelled upon the rails before mentioned, and carrying a steam engine with the requisite machinery for driving a circular saw, which was fixed at the lower end to an upright spindle, and adjusted to the proper level. The spindle was placed between the two rows of piles, and revolved in guides at the end of movable arms, so arranged that it would shift to either side of the dam by turning a handle, and by the same motion it could be pressed towards the pile which was being operated upon until it was severed by the saw. Two piles were usually cut off on each side before the machine required to be moved backwards on the rails. When the way was clear for the pile-cutter, and a sufficient length of dam dredged, sixty piles could be cut off in a day, but the excavators could not keep pace with the pilecutter, and the average uumber of piles actually cut off did not exceed thirty-six daily. The machine was devised by Mr. Charles Murray, of Loman-street, Southwark, and the author, but the motion which regulated the position of the spindle was the invention of Mr. Murray alone, and was patented by him. The total cost of the removal of the dams was £1 48. In cofferdams there was usually a frequent per lineal foot, made up thus: clearing out puddle, settlement of the puddle, producing channels under-13s. 6d.; dredging outside of dam, 7s. 6d. ; cutting neath the bolts and a consequent leakage. In such off piles 3s. per lineal foot. cases, holes were bored, with a 3in. auger, through the inner row of piles, immediately below the tiebolts, and pellets of clay were driven through these into the puddle until the leakage was subdued.

In estimating the pressure to be resisted, and the requisite strength of the dam, the depth of water was taken at 22ft., the piles were assumed to be 12in. square, and the struts 13in. square. The weight of a cubic foot of the dam was estimated to be 1001b., and the breaking strain of the timber, measured by a load upon the middle of a bar 1ft. long and lin. square, was taken at 4001b. The pressure of the water was found to be 15,125lb., or 6-752 tons per lineal foot of dam. The momentum of the water tending to overthrow the dam was 110,916, whilst the momentum of the dam itself was 83,200. It also appeared that if the dam had been 9-23ft. instead of 8ft. in thickness, it would, considered as a wall, have been, in relation to the pressure of the water, in a condition of equilibrium. The resistance of the piles to fracture at the ground line was calculated to be 47,1271b. in relation to a Simultaneously with the construction of these force acting at the centre of pressure of the water. dams, the filling in of the space behind the Temple If one-third were taken as a safe load, the result Pier was going on, the line of the dam was being was 15,7091b. to resist a pressure as before stated dredged, and the driving of the piles begun. The of 15,125lb. Disregarding these resistances, and Temple Pier, 470ft. in length, was irregular in out- reckoning the whole pressure of one bay to act upon line, projecting in some parts upwards of 30ft. in each strut, the thrusts were-on the lower strut advance of the river wall, and the breadth across 222-82 tons, on the middle strut 77.5 tons, and on the foundation trench in the centre part was 57ft. the upper strut 47.94 tons. But with every strut To avoid the necessity of having to use a large resisting an equal pressure the load on each would number of struts of such great length, this dam was be 26-14 tons. For the pressure of the puddle on strengthened by means of buttresses of piles, some- the tie-bolts, the author had no satisfactory data, what similar to those used in the cofferdams con- but he assumed it to be less than that of a similar structed for the Grimsby Docks (Vide Min. of Proc. section of water, and approximately the load upon Inst. C.E., vol. ix., p. 1). These buttresses were the tie bolts was calculated to be at all events less placed at intervals of 20ft., and were backed up by struts extending across the foundation of the pier. The scantlings of the timbers and the sizes of the bolts in this dam were similar to those in dams

than the following amounts: On each lower bolt,
24in. in diameter, 85,250lb.; on each middle bolt,
2in. in diameter, 54,375lb.; and on each upper bolt,
2in. in diameter, 37,625lb.

ROYAL POLYTECHNIC INSTITUTION. HE subject of the present war, which is being discussed in all circles of society, and among all classes of the people, is now being introduced by the proprietors of one of our most popular places of amusement-the Royal Polytechnic Institution, Regent-street. Last night Professor Pepper commenced a very interesting lecture on the subject, accompanied by a series of scenes and representations both by means of photographic and dissolving views. Several of the views have been supplied by M. Paul de Katow, the special correspondent of "Le Gaulois," whose description of the battle of Forbach was introduced into the lecture, others being copies of photographs taken for the Stereoscopic Company. The portraits of the ex-Emperor and Empress of the French, of the King and Crown Prince of Prussia, of Bazaine, and Moltke were alike received with warm expressions of admiration. The lecture, or "entertainment as it is described in the bills, commenced with a panorama of a small portion of the Rhine, including the Valley of the Neckar and the Castle of Heidelberg, and the principal scenes from the war which were represented were the battle of Forbach and some incidents of the struggle about Sedan. Mr. Pepper also exhibited pictures of the cottage before which Napoleon III. and Count Bismarck had their memorable interview, and of the chateau of Bellevue, where the former, still Emperor of the French, surrendered his sword to his royal brother of Prussia. These views are of themselves sufficient to give interest and lend attraction to the entertainment; but they are supplemented by many others, including pictures of Tours, Orleans, Rouen, and Strasburg, and a bird's-eye view of Paris, including its fortifications, as well as representations of different sorts of ordnance, and a dioramic series illustrating

the poetry of war.' Mr. Suchet Champion sang several pieces, and the Praeger Family performed a vocal selection of German and French songs, which included the "Marseillaise" and the "Watch on the Rhine."

THE number of visitors to the South Kensington M.seum during the week ending November 12, 1870, was on Monday, Tuesday, and Saturday (free), from 10 a.m. to 10 p.m., 12,662; Meyrick and other galleries, 1,489; on Wednesday, Thursday, and Friday (admission 6d.), from 10 a.m. till 4 p.m., 1,887; Meyrick and other galleries, 96; total, 16,134. Average of corresponding week in former years, 9,386. Total from opening of Museum, 9,952,198.