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which should be as hard as possible. Watch-spring steel is | meridian, its north pole of course pointing north. For sometimes used, and file steel is recommended by some convenience this magnet should be mounted on a vertical authorities. The hardness is important for two reasons, graduated rod, with a rough and a fine adjustment. in the first place, to ensure that the permanent magnetism In adjusting the sensiof the needle shall not alter. This is of small importance tiveness of the galvanowhere permanent deflections are to be observed, provided meter, it will be useful to we can be sure that the direction of the magnetic axis does recollect that the couple not alter. In the second place the induced magnetism is tending to bring the less in hard than in soft steel, though not so much less as needle back to its posisome writers would lead us to suppose. The best way of tion of equilibrium varies avoiding induced magnetism would be to make the needle directly as the square of spherical in form; the advantage thus gained, however, the number of oscillawould in most cases be counterbalanced by other defects. tions which the needle The form of the needle has been much varied by different executes in a given time constructors. In the earlier instruments they were made when no current is passvery long, and were suspended like compass needles by means ing through the multiof a jewelled cup playing on a steel point. We have heard plier. As the astatizing on good authority that for some purposes, such as mounting magnet is brought nearer Fig. 2. tangent galvanometer needles, this method of suspension, if and nearer to the galvanometer, the oscillations of the needle carefully carried out, really answers very well. By far the will be seen to become slower and slower, till at last the most usual mode of suspension, however, is by means of a equilibrium becomes unstable, and the needle turns round raw silk fibre, or by a bundle of such fibres. Weber in- through 180°; after which, on causing troduced the use of heavy magnets whose moment of inertia the magnet to approach still farther, and time of oscillation were great. For many purposes the rapidity of oscillation increases. such needles have great advantages-where, for instance, If the damping be very strong, and the the time of oscillation, the logarithmic decrement, or the mirror very light, an intermediate stage extent of swing of the needle has to be observed. Where, called the aperiodic state is passed on the contrary, the galvanometer is to be used merely as through. an indicator, particularly in detecting transient currents, a light needle of small moment of inertia should be used. Continental constructors, no doubt unduly influenced by a reverence for Weber's methods, have failed to realize this; and we have seen few, if indeed any, instruments by them really well suited for measuring resistances with the Wheatstone's bridge. This principle has been carried farthest in the galvanometers of Sir William Thomson, in some of which the needle with all its appurtenances weighs little over a grain.

In some galvanometers (e.g., certain telegraphic reading instruments) the needle is movable about a horizontal axis, and is weighted so as to be vertical in its undisturbed position. Owing to the friction at the points where the axis is supported, this method of suspension is useless for sensitive instruments.

3. When, as is usual, the galvanometer magnet is movable in a horizontal plane, the force which balances the electromagnetic force of the current in the multiplier is the horizontal component of the earth's magnetic force. Each of these forces is proportional to the magnetic moment of the galvanometer needle, and consequently the ratio of the forces, on which depends the magnitude of the deflexion of the needle, is independent of the magnetic moment of the needle. We cannot therefore increase the sensitiveness of the galvanometer by simply increasing the magnetic moment of the needle. The action of the earth can, however, be counteracted, and the needle rendered more or less astatic in one or other of two ways.

One way is to fix on the same axis of suspension two parallel magnets, whose magnetic moments are as nearly as possible equal, and which are turned opposite ways. The whole system is suspended so that one of the magnets swings inside the multiplier and the other over it, as in fig. 2. In more modern instruments, such as those constructed by Messrs Elliot Brothers, the multiplier consists of two equal coils placed one vertically over the other, each enclosing one of the magnets of the astatic system, as in fig. 3. Another method is to place a magnet, or a system of magnets, in the neighbourhood of the galvanometer, so as to counteract the earth's force. In general, one magnet will suffice, placed vertically under or over the galvanometer, in the magnetic

4. The normal position of the magnetic axis of the needle, when no current is passing, is parallel to the windings of the multiplier. It is particularly necessary that it should be in this position when the galvanometer is being used as a measuring instrument, and it is advisable in any case, since this is the position in which for a given current the Fig. 3. electromagnetic action on the needle is greatest. The final adjustment might of course be made by moving the multiplier, but it is far more convenient to move the needle, a magnet being used for the purpose. Sometimes the astatizing magnet is used, but it is better to have a much weaker magnet for the fine adjustment, suspended like the astatizer on a vertical axis, having a vertical motion and a motion of rotation. rotation. It is better still to use a magnet placed with its axis in the axis of the multiplier, so that it can be slid backwards and forwards at pleasure. We have seen two such magnets placed side by side, with their north and south and their south and north poles together; this gives a differential adjustment which is very convenient. The main advantage of placing magnets in this way is that we can alter the direction of the lines of force with a minimum effect on the strength of the magnetic field.

5. The graduation or reading apparatus in the older instruments consisted of a pointer or index fixed to the magnet (very often it was the magnet itself), playing over a circular graduation centred as nearly as possible in the axis of rotation of the needle. The mirror method of reading which prevails in most modern instruments was originally suggested by Poggendorff, and carried out in practice by Gauss and Weber. A mirror is rigidly attached to the magnet, so that the reflecting face passes as nearly as possible through the vertical axis of rotation of the needle. The glass of the mirror should be very thin, otherwise a greater or less correction for its thickness will be necessary. In the subjective method of reading, a scale is fixed before the mirror, which is usually plane (it must be well made to

1 This is not exactly true where there is damping: but the rule is sufficient for ordinary purposes.

be of any use), and the image of the scale is observed by | coil is of flat, rectangular shape, with a narrow central means of a telescope fixed over or under the centre of the opening just large enough to allow one of the magnets of scale. The scale divisions are seen to pass the wires of the the astatic system telescope, and if a circular scale be used, whose centre is in to swing freely. the axis of suspension of the mirror, the difference between The other magnet the numbers on the cross wires in any two positions of the swings over a gramagnet is a measure of twice the deflection of the magnet. duated circle placed A correction is necessary when a straight scale is used. The on the top of the reader who has occasion to use the method will find prac- coil, and serves also tical instructions, with tables of corrections, in Wiedemann's as an index. SomeGalvanismus, Bd. ii. sec. 181 sqq.; Maxwell's Electricity times a mirror and and Magnetism, vol. ii. sec. 450 sqq. In the objective scale are substituted method, which is more usually practised in this country, the for the index and mirror is concave, and reflects the image of a fixed illumin- graduated circle. ated slit (often furnished with a vertical wire where greater The sole on which accuracy is desired) upon a graduated scale. The readings the coil stands is are proportional to double the deflexion of the needle, or movable on a fixed to the tangent of the double deflexion, according as the piece which can be scale is circular or straight. levelled by means of three screws. A graduation is often furnished to measure the angle of rotation of the coil about vertical FIG. 4.-Astatic multiplier. axis; this is useful when the galvanometer has to be graduated or corrected for the torsion of the fibre.

There is

6. By damping is meant the decrease of the extent of the oscillations of the galvanometer needle arising from the dissipation of energy through the resistance of the air, the action of currents induced in neighbouring metallic circuits, the viscosity of the suspension fibre, and so on. always more or less damping owing to the first two causes, and possibly the third; but in many cases, where it is desirable that the oscillations should subside very quickly, the damping is purposely increased. In the older instruments the damping arrangement consisted of masses of copper surrounding the magnet. This is carried to the extreme in Wiedemann's tangent galvanometer, where the needle is ring-shaped, and swings in a ring-shaped cavity not much larger than itself, in the heart of a mass of copper. In the dead-beat galvanometers of Sir William Thomson the magnet with its attached mirror is enclosed in a flat cell, in which it can just move freely to the required extent. The damping, due to the pumping of the air backwards and forwards round the edges of the mirror, is so great that the needle swings off to its position of equilibrium, and remains there without oscillating at all. The same result is attained in Varley's construction by immersing the needle in a cell filled with liquid.

7. The box of shunts is simply a set of resistances; generally there are three,-th, th, andth of the resistance of the multiplier. When it is required to reduce the sensibility of the galvanometer, the terminals of one of these, say theth, are connected with the terminals of the multiplier; we thus have a multiple arc in place of the galvanometer, and the current is divided between its branches in the ratio of their conductivities, so that onehundredth1 of the whole current flows through the galvanometer. By means of such a box as we have described, we can therefore send through the galvanometer the whole of any current, or the tenth, hundredth, or thousandth part. It must not be forgotten that the introduction of the shunt diminishes the whole resistance of the galvanometer circuit. In most cases, however, this is of little moment; where necessary, the alteration may be either compensated 2 or allowed for.

Sensitive Galvanometers.-In galvanometers of this class everything is disposed so as to bring the greatest possible number of turns of wire into the neighbourhood of the needle. The needle is therefore made as small and compact as possible, and the windings embrace it as closely as possible, the opening in the centre of the coil being reduced to a minimum. The astatic multiplier (fig. 4) is an instrument of this kind which was formerly much used.

1 See art. ELECTRICITY, p. 43.

The

2 E.g., in above case by introducing into the galvanometer circuit ths, ths, ths, respectively of the resistance of the multiplier.

a

In the galvanometers of Sir William Thomson, which are the most sensitive hitherto constructed, the central opening of the coil is circular, being just large enough to allow free play to a small concave mirror a centimetre or so in diameter. Usually the coil is wound in two halves, which can be screwed together with a septum between them, in which is placed the arrangement for suspending the mirror and magnets. In dead-beat instruments the coil is often wound in a single piece, and the mirror is arranged in a cell, glazed back and front, and fitted into a tube which slides into the core of the coil.

Fig. 5 represents a very convenient form of Thomson's

FIG. 5.-Form of Thomson's Galvanometer.

It was constructed

galvanometer, the only specimen of its kind we have seen.
The peculiarity of its construction consists in the connexion
between the scale and the galvanometer, which saves much
trouble in adjusting the instrument.
by Elliot Brothers for the British Association Committee
on Electrical Standards. Such a galvanometer as this, pro-
vided with a high and low resistance coil, would meet all
the wants of most laboratories.

In another form called the marine galvanometer, the mirror is strung on a fibre stretched between two fixed points. In order to keep the needle from being influenced

3 This arrangement is that adopted by White of Glasgow in the galvanometers made by him after Sir Wm. Thomson's pattern.

by the rolling of the ship, its centre of gravity is carefully adjusted so as to be in the axis of suspension. The mirror is enclosed in a narrow cell which just allows it room to deflect to the required extent, and damps the oscillation so effectually that the instrument is "dead beat." In order to destroy the directive action of the earth, the inconvenience of which in a galvanometer for use on board ship is obvious, the case of this galvanometer is made of thick soft iron, which completely encloses the whole, leaving only a small window for the ingress and egress of the ray of light by means of which the motions of the mirror are read; a flat horse-shoe magnet placed on the top of the case still farther overpowers the earth's force and directs the mirror.

All these galvanometers may, of course, be wound double and used differentially. When this is the case, a small auxiliary compensating coil is often used to correct the inequality of the magnetic fields due to the two sets of windings. This auxiliary coil is usually mounted on a spindle in the axis of the main coil, and can be moved backwards and forwards till a current passing through it and one set of windings in one direction, and through the other set of windings in the other direction, does not sensibly deflect the mirror.

The astatic arrangement described above (p. 51, fig. 4) is often adopted. A galvanometer of this construction by Elliot Brothers is shown in fig. 6. It may be questioned, however, whether for ordinary purposes the additional sensibility thus gained compensates for the increased complexity and cost of the instrument.

It

Standard Galvanometers.When galvanometers are intended for measuring currents, there must be some law connecting the indications of the needle with the strength of the current in the multiplier. is therefore of great importance that slight variations in the position of the magnet should not introduce large or irregular (incalculable) variations into the indications of the instrument. Accordingly in standard instruments the windings are much farther removed from the magnet than in sensitive galvanometers, and in the best forms the multiplier is so disposed that it produces a uniform field of magnetic force around the needle.

FIG. 6.-Elliot's Astatic Galvanometer.

The earliest forms of standard galvanometer were the tangent and sine compasses invented by Pouillet. The first of these consists simply of a single vertical coil of wire, with a magnet suspended at its centre, whose deflexion may be read in any of the various ways already described. If the length of the magnet be very small, the magnetic field in its neighbourhood may be regarded as uniform, and the electromagnetic couple will be proportional to cos 0, 0 being the deflexion from the plane of the windings. If the windings be arranged so as to be in the magnetic meridian,1 the couple due to the earth's action tending to bring the magnet back to its position of equilibrium will be proportional to sin 0, hence the current strength will be proportional to tan 0.

1 This can be done most easily by means of a mirror attached to the multiplier and adjusted so as to be parallel to the windings.

may

If the multiplier be movable about a vertical axis through angles which can be measured in any way, the instrument be used as a sine compass. The current is applied and the multiplier turned round after the magnet until the axis of the latter is again parallel to the windings. The current strength is now clearly proportional to sin 0, where 0 is the deflexion of the multiplier from the magnetic meridian. When the instrument is used in this way, the needle being always brought into the same position relative to the windings, the uniformity of the magnetic field is a matter of indifference, and there is no necessity for the needle to be short.

Gaugain attempted to improve the tangent galvanometer by suspending the magnet excentrically at a point in the axis of the coil distant from the centre by half the radius of the coil. This, however, is in reality the reverse of an improvement.2

A real advance, however, was made by Helmholtz, who placed two equal parallel and vertical coils, one on each side of the magnet, each at a distance from it equal to half the common radius. In fig. 19, at the end of his second volume, Maxwell gives a diagram of the lines of force due to two equal parallel circular circuits, from which it will be seen that the magnetic field at the centre of such an arrangement of currents is very approximately uniform. This approximation may be carried

wire is wound in two parallel

channels cut in a cylindrical block of hard wood, each an inch broad and an inch deep. The radius of the bottom of each channel is one

them is half an inch. The cylindrical perforation in the core of the multiplier is 14 inch in diameter-large enough to allow the needle to swing freely without Into the ends of the core are screwed two caps containing a piece of plane parallel glass and a

still farther by adding a third FIG. 7.-Galvanometer designed coil parallel to the two others, by Professor Maxwell. and equidistant from them. The In some examples of Helmholtz's galvanometer the windings are arranged on a conical inch, and the distance between surface, so that the ratio of the radius of each to the distance of its plane from the centre of the magnet shall be 2:1. In causing irregular air currents, &c. reality this is unnecessary, provided the ratio of the depth and breadth of the usual rectangular channel be properly adjusted (see Maxwell, vol. ii. sec. 713). Fig. 7 represents a galvanometer of the kind mounted, so that the galvanometer described.

plano-convex lens respectively, the

former for subjective, the latter for objective reading. By means

of a slit and screw in the stem

which supports the instrument, a horizontal bar can be fixed parallel to the axis of the multiplier. On this a deflecting magnet can be can be used as a magnetometer.

Reduction of Galvanometer Indications.-When the position of every layer of wire in the multiplier is known with sufficient accuracy, and the multiplier arranged so as to produce a sensibly uniform field, the electromagnetic action per unit of current can be calculated for every position of the magnet. In this case the galvanometer is an absolute instrument. When we possess one absolute instrument it is easy to evaluate the indications of any other in absolute measure by means of it; we have only to pass the same current through both galvanometers in series and compare the readings. The best way, however, to construct a standard galvanometer is to provide for uniformity of field in the core of the multiplier, and find the resultant electromagnetic force for unit current, or, as it is called, the constant of the instrument, by comparison with a pair of equal standard coils of large diameter (18 in. to 24 in.). These are arranged vertically on the same axis, the distance between them being equal to the mean radius, just as in Helmholtz's galvanometer. The galvanometer to be tested is placed symmetrically between the

See Maxwell, Electricity and Magnetism, vol. ii. secs. 712, 713.

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H being the horizontal component of the earth's magnetic force. In many cases it is necessary to correct for the torsion of the suspending fibre. The value of this correction is easily found by turning the multiplier through 90° either way, and observing how far the needle follows it. The reader will find all necessary details in Maxwell, vol. ii., secs. 452, 742.

In all cases where great accuracy is required it is advisable to graduate, or, as it is sometimes said, to calibrate the galvanometer, that is, to compare the electromagnetic couple exerted by the multiplier when the needle is deflected through an angle 0 with that when the needle is parallel to the windings. It is easy to see that this may be done by means of the arrangement described above for finding the constant of a galvanometer. If the object simply is to calibrate the galvanometer without reducing its indications to absolute measure, the standard coils may be replaced by a single coil of sufficient magnetic moment placed in the axis of the multiplier. Another method of calibration, which is simpler, and in some respects more satisfactory, although possibly more laborious, will be understood from fig. 9. The resistance a is equal to the

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resistance of the galvanometer, and they can be rapidly interchanged. By adjusting f the ratio of the currents in the branches of the multiple arc may be varied as we please, and by varying the current in one of the branches can always be brought to a standard strength, say that which produces unit deflexion of the galvanometer needle. We can thus, by repeatedly interchanging a and b, compare the deflexions produced by a series of currents whose strengths are given multiples of the standard strength. If the experimenter has two galvanometers at his disposal the interchanges may of course be avoided.

On the Use of the Galvanometer.-We may add a few remarks on the different uses to which a galvanometer may be put. Detection of Currents.-One of the commonest of all the uses of a galvanometer is to indicate the currents sent through telegraph wires or cables. In the case of submarine cables, where the currents are often very feeble, dead-beat galvanometers of Thomson's or Varley's construction are used.

When a current is to be detected which produces a very small or quite insensible permanent deflexion, the following process, called the method of multiplication, is sometimes used. The period of oscillation of the needle is first found; then, the needle being at rest or only swinging through a very small arc, the current is applied 1 See for such calculations Maxwell, vol. ii., chaps. xiv. and xv. Or the piece to which the fibre is attached, if it is not rigidly attached to the multiplier.

through half the period of oscillation so as to urge the needle in the direction in which it is going, then intermitted for half a period, then applied again, and so on. If a current in the supposed direction really exist, the oscillations of the magnet will gradually increase, until the energy supplied by the intermittent action of the current is equal to that wasted by the damping of the needle.

It is obvious that this process is more effective the smaller the damping of the needle; it leads to no advantage whatever with a dead-beat instrument.

Resistance Measuring.-In comparing resistances, sensitive galvanometers of Sir William Thomson's construction 3 are by far the most convenient; the dead-beat arrangement is essential for rapid work.

If a differential galvanometer of given dimensions be used (sce art. ELECTRICITY, p. 44), and if the resistance of the battery is negligible compared with the other resistances used, the wire with which it is wound should be chosen so that its resistance is onethird of the resistance to be measured.4

It is shown in the art. ELECTRICITY (p. 44) that, in arranging a Wheatstone's bridge to measure a given resistance, all the arms of the bridge and the battery and galvanometer should have equal resistances. As a rule, all these are not at our disposal. If the resistances of the arms and of the battery are given, and the resistance of the galvanometer (of given dimensions) is at our disposal, then the resistance of the galvanometer ought to be equal to that of the multiple arc which remains between the terminals of the galvanometer when the battery is disconnected from the bridge." This may be deduced at once from the expression given in vol. viii. P. 44.

Again, the resistance to be measured and the battery and galvanometer resistance being given, we may inquire what is the best arrangement of the arms of the bridge.

Differentiating the expression given in vol. viii. p. 44 with respect to y and z, we get

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R+B R+G'

RG S=

2=

B(R+G); R(R+B)

T= RB.

R+G, and UBG,— R+B'

whence we have determining the resistances of the disposable arms. It appears that, when B and G are given, the resistance of the arm opposite to the resistance to be measured ought always to be the geometric mean between B and G.6

In a certain class of observations a needle with large moment of inertia is used. The methods in use are mostly due to Gauss and Weber. For an account of these methods the reader is referred to Maxwell, chap. xvi. He should also consult a paper by Du Bois Reymond in Monatsber. d. Berl. Acad., 1869-70. (G. CH.)

GALVESTON*

Copyright, 1879, by A. & C. Black.

Geras, United

YALVESTON, a city and port of entry on the coast of Texas, United States of North America, situated about 340 miles to the westward of the mouth of the South Pass of the Mississippi River, on the south side of the entrance into Galveston Bay, in 29° 18' N. lat. and 94° 47' long. west from Greenwich. It is the principal port and the largest city in the State, is the seat of justice of Galveston County, and is located on the inner shore of Galveston Island, about 2 miles from its most north-easterly point, known as Fort Point. The city therefore faces the main Texas shore, being separated from it by West Bay, lying between the island and the mainland. The principal portion of the county lies on the mainland fronting the two bays above named, its general surface, like that of the island, being low and level, and the soil sandy.

Galveston Island is a low sandy island, about 28 miles long and 1 to 3 miles wide, stretching along the coast of Texas in a north-easterly and south-westerly direction, and forming the gulf coast-line throughout its entire length. 3 See Sir W. Thomson on resistance measurement, Proc. R. S., 1862, p. 313.

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Its surface, which has an average height of 4 to 5 feet above tide level, is diversified by a number of freshwater ponds and intersected by several creeks and small bayous. The beach, on the Gulf side, furnishes a smooth and pleasant drive during low-water stage, and excellent surf-bathing at all times. To the northward of the entrance into the harbour, the coast-line is continued in the same general direction to the north-east by Bolivar Peninsula, a low, narrow sand-strip of the mainland, the width of the throat of the harbour between Fort Point and Bolivar Point being about 2 miles. There is a lighthouse on Bolivar Point.

Galveston Harbour is the finest in the State; and the bay of the same name, including certain outlying portions of it known severally as East Bay, West Bay, and Turtle Bay, covers an area of upwards of 450 square miles of tidal water. At the head of the bay, about 35 miles from the city in a northerly direction, it receives Trinity River, its largest tributary, while San Jacinto River and Buffalo Bayou enter it from the west 18 miles lower down.

The mean rise and fall of tide at Galveston is 1 feet, but springtides occasionally rise more than 3 feet above, and fall nearly 2 feet below the plane of mean low water, and fluctuations between much wider limits are not uncommon under the influence of heavy winds. During a storm which occurred in October 1867 the water rose 6 feet above mean low-water stage, and in September 1875 it rose in some portions of the bay 7 feet, and in others 9 feet above the same level. Two years later there was a rise of 5 feet, produced by an onshore wind which reached a maximum velocity of 60 miles per hour. The lowest tide of which we have any record fell 3 feet below mean low-water level, thus giving a difference of 127 feet between the highest and the lowest recorded tides.

A sand bar, produced and maintained by the joint action of waves and currents, stretches across, bow-shaped, in front of the entrance into the bay, restricting the draught of vessels entering the harbour to from 12 to 13 feet. The United States Government has undertaken the improvement of this entrance by means of two jetties, one starting from Fort Point and the other from near Bolivar Point, having an aggregate length of about 7 miles. It is the intention to carry them out to and beyond the crest of the bar on converging lines, so that their sea ends, resting in about 18 feet water on the outer slope of the bar, will be about 1 mile apart. It is expected that these jetties will cost about $2,000,000, and that they will produce and maintain a practicable channel depth of 18 to 19 feet at mean low-water. Once inside this bar a draught of fully 20 feet can be carried to the wharves of the city. The Bolivar Point Jetty in August 1879 had reached a length of 8,000 feet from the shore. That from Fort Point had not been carried out so far. The peculiar mode of construction adopted for these works by the superintending engineer, Major C. W. Howell, United States Corps of Engineers, merits some notice here. The jetties are formed with large gabions, or basket-work cylinders, plastered inside and out with hydraulic cement, so as to give a thickness of 5 to 6 inches to the cylindrical wall. The gabions are either circular, with a diameter of 6 feet, or of an oval cross section, with diameters of 6 feet and 12 feet respectively. They are closed at the bottom, and are also provided with a tight-fitting wooden cover. After being sunk to their proper positions in the work, on their ends, arranged in a single or double row, they are filled with sand pumped up from the bottom and passed in through a hole left in the gabion cover. At first these gabions were placed directly upon the bottom, but the action of the sea and currents caused so much underscour and settlement, that a foundation of fascines formed into a mattress and weighted with stones was resorted to. On the most exposed portions of the works about one-sixth of the number of gabions put into position have been destroyed by heavy storm-waves, so that this method of construction cannot as yet be regarded as past the experimental stage. Galveston was first settled in 1837. It is handsomely laid out upon ground elevated from 6 to 10 feet above ordinary tide level, has wide and straight streets, and has several public squares, parks, and gardens. The streets running parallel to West Bay are known as avenues, and are designated by the letters of the alphabet, beginning at the bay, while those at right angles to the water are numbered. Special names are assigned to some of the streets. Avenue A, parallel and next to the wharf or channel front, is mostly occupied by wholesale houses. Next comes Avenue B, or "The Strand," and then Avenue C, or Mechanic Street, both devoted largely to the wholesale business. Avenue D, or Market Street, for a distance of seventeen squares, is occupied by retail stores, shops, restaurants, hotels, banks, &c. This is the main shopping street. Avenues E and F are of the same character. The post-office and United States court-house are at the intersection of Avenue F and 20th Street, and the custom-house is near by. Avenue J, or Broadway, is regarded as the most desirable locality for residences. It is 150 feet wide, including an esplanade 36 feet wide through the middle and a 16-foot sidewalk on either side. Bath Avenue

at right angles to Broadway, is 120 feet wide. Fremont, or 23d Street, is the principal drive in the city, and is maintained as a shell road from "The Strand" to the Gulf beach. With the exceptions named, the streets are 80 feet and the avenues 70 feet wide, including 16 feet sidewalks, and the blocks or squares are uniformly 260 wide and 300 feet long, with an alley 20 feet wide running lengthwise through the middle, along the rear of the lots. The portion of the city built over extends from about 6th to 40th Streets, and from Avenue A south to within two to three blocks of the Gulf beach. The only streets paved are four or five blocks on Avenues B, C, and D. They are paved with blocks of heart cypress. The same avenues are shelled from between 10th to 32d Streets, or thereabouts, with clam shells from 18 to 30 inches deep. Trees are planted very generally on the outer edge of the sidewalks, the oleander being the chief growth. It frequently attains a height of 20 to 25 feet, and grows rapidly from slips with great luxuriance, blooming the year round. The fig, orange, the black Hamburg and other kinds of grape, and many varieties of flowers and evergreen shrubbery, thrive and flourish. Throughout the most thicklysettled portions of the city the sidewalks are paved with either asphaltum, concrete, brick, or German or English tiles. Oleander Park embraces 80 acres, and the city park about 25 acres, and there are three public gardens and six public squares. The business portion of the city is built up mostly with brick, and within certain defined fire limits the erection of wooden buildings is prohibited.

Among the public buildings, other than churches, are a post-office, custom-house, United States court-house, a county court-house, a county and city prison, a city hall, an opera house, 7 public halls, 2 libraries, 2 theatres, 13 hotels of different grades, and 3 market houses. There are 30 schools of all kinds, 15 church edifices, a Roman Catholic university or college (St Mary's), a medical school, a convent, a house of refuge, an orphan asylum, and 3 hospitals. The St Mary's university was founded in 1854, and in 1872 had 8 professors and 35 collegiate and 115 preparatory students. The medical school, founded in 1864, had ten years thereafter 6 professors. The convent (Ursuline) has 25 nuns and a female academy connected with it. There are two other female academies in the place. There are published in the town a number of daily, triweekly, and weekly papers. Galveston is a bishop's see of the Roman Catholic Church. The city is well connected by railroad with different parts of the State, and by regular steamship lines with Liverpool, New York, Havana, New Orleans, and the ports of Texas. The Galveston, Houston, and Henderson Railroad crosses West Bay on a wooden bridge 2 miles long, and by means of the Galveston Wharf Railroad delivers and receives freight at the several wharves of the city. The Gulf, Colorado, and Santa Fé Railroad, now building from Galveston to Belton, in Bell County, a distance of 220 miles, is finished (September 1879) as far as Richmond, a distance of 63 miles, and 57 miles more to Brenham will be finished by January 1, 1880. The entire road to Belton is to be completed by September 1881. This road crosses the Brazos River, below Richmond, on an iron bridge, and has a wooden bridge of its own across West Bay. There are no highway bridges connecting Galveston Island with the mainland.

The cotton business of the place is represented by six cotton presses and many immense brick warehouses, furnishing storageroom for nearly 200,000 bales of cotton, and covering an area of more than 50 acres. There are two national banks, with an authorized capital of $800,000, and a paid-up cash capital of $300,000,the aggregate paid-up capital of all the banks being upward of $2,000,000. The assessed value of real estate in 1878 was over $20,000,000, and the bonded debt $1,200,000.

Galveston is a healthy city, possesses a delightful climate, and has not been afflicted with an epidemic disease since 1867.

The following table, giving the temperature, the barometric pressure, and the rainfall at this place for five years ending June 30, 1878, has been compiled from the reports of the Chief Signal Office, United States Army:

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