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Dr. Leach has given some measurements,&c., | bulb at each extremity. The one bulb is halfof the class of boats known as the Rochester filled with ether, in which the bulb of a delibarge, the cabins of which are usually very cate thermometer is immersed; the other is clean; still the above table clearly shows how covered with muslin. extremely deficient these vessels are in cubic An observation is taken as follows: The space, air, and light,
muslin is wetted with other, the evaporation Summary. What is required, then, is firstly of which quickly cools the bulb and condenses systematic inspection of every vessel, whether the vapour of ether with which it is filled. an ocean-going vessel, an emigrant ship, a coast- As a consequence, evaporation goes on rapidly er, or even a canal-boat, by competent medical from the liquid ether in the other bulb, and inspectors, whose duty would be to see that all its temperature falls. The outside of the legislative enactments relative to the health, bulb is narrowly watched, and directly a ring comfort, safety, or convenience of the crew of dew is deposited, at that instant the therwere carried out. It is obviously absurd to mometer is read. The great objection to this enact laws, and provide no adequate machinery hygrometer is that every observation entails for the purpose of seeing that they are carried a trifling expense. It has generally given out. It is true that the medical officer of health place tois responsible for the port to which he is ap- The Dry and Wet Bulb Thermometers.pointed (see SANITARY AUTHORITIES, PORT), Now this is simply a special arrangement of but in large ports there ought to be a syste- two ordinary thermometers, and any two will matic ship survey. The duty of such inspectors do, providing they are both constructed of would be to see that a sufficient, and suffici- exactly similar materials, and, as a matter of eutly varied, supply of food was provided; convenience, are adjusted to the same scale. that the passengers or sailors were in good The one thermometer is simply hung on a health ; that, in the case of ocean-going ves- board near the other, whilst the second has sels, there was a supply of lime - juice or its bulb covered with thin muslin (which vegetables on board ; that there was ample must be clean and free from starch). A few provision for water-supply; that emigrants, threads of the muslin are led into a vessel passengers, or men had the cubic space as laid containing distilled water. The bulbs of both down by the Duke of Richmond's Act; and thermometers project below the scales. The special attention should be directed to the necessary precautions in the use of these therforecastle in ships where there is no deck mometers are, to see that the muslin is wethouse, and to the arrangements for cooking the muslin must be either wet, or, in case of and ventilation. Under - manning or over- temperatures below freezing-point, frozen-and crowding could, under such a system, hardly if the teinperature should rise above freezingfail to be observed and prevented. All ves- point, the muslin still remaining frozen, it sels carrying passengers, and of any size, must be thawed before an observation is taken. should carry a surgeon, whilst the drugs The extreme importance of observations of supplied to ships should be examined by the the difference of temperature between the analyst under the Adulteration Act previous two thermometers may be gathered from the to final shipment. If measures such as these fact that by their aid the following facts can were carefully carried out, there is great be ascertained :reason to hope that much preventable waste
1. The dew-point. of life would be decreased; but at the same 2. The elastic force of vapour, or the amount time it must be confessed that many of the of barometric pressure due to the vapour lower class of sailors are addicted to filthy present in the atmosphere. habits, and require sanitation in their own 3. The quantity of vapour in a cubic foot persons as much as the vessels themselves. of air. See HOSPITAL SHIPS; VENTILATION; SHIPS; 4. The additional vapour required to satuSANITARY AUTHORITIES, PORT; SCURVY, rate a cubic foot of air. &c.
5. The relative humidity.
6. The weight of a cubic foot of air at the Hygrometer-An instrument used for time of the observation. the purpose of determining the amount of The dew-point and elastic force of vapour aqueous vapour in the air.
are both determined by Dr. Apjohn's formula, The most accurate hygrometers are those and by the aid of Table I. constructed, like Daniell's and Regnault's, on Let F be the elastic force of saturated the principles of condensation and evapora- vapour at the dew-point, f the temperature of tion.
the wet bulb-in other words, the elastic force Daniell's hygrometer consists of a glass at the temperature of evaporation-d the tube bent at right angles at the points, with a l difference between the dry and wet bulbs,
and h the barometric pressure, then, when If the dry bulb read 50°, the wet 45°, and the wet-bulb reading is above 32° F.
the thermometer stands at 29 inches, what is d h
the elastic force of saturated 'vapour at the F=f88 30
dew-point, and what is the dew-point?
By Table I. the numbers opposite the wetand when below 32° F.
bulb temperature is •299; then f = 299, d = d h F = fх
50 – 45o = 5°, and h = 29 inches. 96 30
5 F = 299
= 244 d and h are, of course, obtained by observa
88 30 tion, f is found in Table I., and F is then the which is the elastic force of saturated vapour only unknown quantity, and is quickly found at the dew-point; and on referring to Table I., by calculation, and from F, by Table II., the the temperature opposite 244 is 397, which dew.point is obtained thus :
is the dew-point itself.
TABLE I.—Showing the ELASTIC Force of AQUEOUS VAPour in Inches of Mercury from
0° to 80°, calculated from the Experiments of REGNAULT. From Mr. GLAISHER's Hygrometric Tables. The intermediate Tenths of Degrees may be easily interpolated.
The use of Table II, is to obviate the fore- ence of temperature of the two balbs. going calculations. In order to determine the thus:dew-point of the foregoing example by Table
2.06 x 5 = 10:3 II., it is merely necessary to take the factor Now subtract this from the dry-balb teraopposite the temperature of the dry bulb-perature and the product is the dev-port viz., 2.06—and multiply it by the differ- | 50 - 10:3 = 39-7, as before.
TABLE II.-FACTORS for Multiplying the Excess of the Dry-Bulb Thermometer over that
of the Wet Bulb, to find the Excess of the Temperature of the Air above that of the Dev-Point. From Mr. GLAISHER's Hygrometric Tables.
The relative humidity, &c., are best deter- | the dew-point be 29:4°—that is, below freezingmined by the aid of Mr. Glaisher's tables, point--there will certainly be frost. See Air, which every practical meteorologist should BAROMETER, WIND, &c. possess. The determination of the dew-point is, however, of the most importance-one of Hyoscyamia--The active principle of the its most evident applications being the pre- | Hyoscyamus niger, also found in the thorndiction of frost. If the dew-point in the even- apple, Datura Stramonium. It may be obing be well above freezing-point, no matter tained in silky crystals ; very soluble in alcohol how clear and frosty-looking the sky may and ether. It is difficult to recognise by chelook, the absence of frost may be with some mical tests. Sulphuric acid turns it brown. confidence predicted; if, on the other hand, See DATURIA, &c.
Ice-Water at a temperature below 32° F. Ice is used in medicine for the purpose of (Oʻ C.) freezes and becomes ice. At the mo- allaying sickness, inflammation, hæmorrhage, ment of congelation it increases in bulk about and lately it has been recommended as a reone-twelfth, and expands so forcibly as to burst medy in the treatment of diphtheria. It is the vessel in which it is contained. The most also used in hot weather for the preservation compact ice has a specific gravity of *923. of fish, game, meat, butter, &c. Most large 1000 parts of water at 0° C. become dilated on establishments are now furnished with an ice freezing to about 1083. Water in freezing room or chamber, and ocean-going steamers becomes much purer, losing a large portion, also contain this necessary appliance. sometimes the whole, of its saline contents, Ice is preserved during the summer months and the air is expelled ; hence ice-water may by confectioners, &c., in a drained well or exbe considered tolerably pure. The ice froni a cavation, somewhat of the form of an inverted good fresh-water spring is perhaps the purest sugar-loaf, contained in a small shed or buildwater in nature.
ing called an icehouse. This building should
always be situated on a dry sandy soil, and if
Oz. Grs, Percentage.
Water possible on an eminence, with the door on the
2 140 14 5
Albuminoid, nitrogenous, or north side, and the roof conical and thickly flesh-forming matters
332 11-9 thatched with straw. There are now many
9 402 62 0 machines for the manufacture of ice, and the
Sugar, guin, &c.
1 110 17 cost of making it ranges from 2s. 6d. to 10s. Cellulose per ton. Sufficient cold is obtained in some
Mineral matter of the machines by the quick evaporation of
1000 liquid ammonia from compressed ammoniacal gas, and in others it is produced by the expan
Composition of Dried Maize (Payex',
12.50 sion of compressed air.
67-35 The custom of eating ices after a hearty and Dextrine
4.00 varied meal cannot be too strongly condemned,
Cellulose since the sudden cold stops the flow of gastric Mineral matter
1.25 juice. Thus digestion is interfered with, and if the practice is persisted in, dyspepsia is in
100-00 evitable. See FREEZING MIXTURES, &c.
By the aid of the microscope it may be Iceland Moss-See LICHEN.
seen that the testa of Indian-corn is composed
of two membranes, the outer of which is made Improvement Act, Improvement up of several layers of oblong cells, the inner Act Districts-An “Improvement Act” of only a single layer of cells. The cells of means an Act for regulating and managing the cellulose make up the remainder of the the police of, and for draining, cleansing, seed. They form a cellulated network, each paving, lighting, watching, and improving, a space holding a starch corpuscle. The starch place; or it may be an Act for any one of corpuscles show under the polariscope a black those purposes.
cross. They are disc-shaped, with a central “Improvement Act District” means any concavity, and generally show a divided aod area for the time being subject to the juris- radiate hilum (see fig. 51). diction of any commissioners, trustees, or other persons invested by any local Act with powers of town government and rating, and empowered under the Local Government Acts to adopt those Acts, or any parts thereof.
Every Improvement Act district is now an urban sanitary authority.
Provision is made by P. H., s. 310, in case of an Improvement Act district or local gov. ernment district becoming a borough, that all rights, duties, liabilities, &c., of the Improvement Act district, or local board, as the case may be, shall pass to, and be vested in, the council of the borough. See SANITARY DISTRICTS.
Indian-Corn-Common maize or Indiancorn (Zea Mays) is a native of tropical America, and is now extensively cultivated in the United States, Africa, Southern Europe, Germany, and Ireland. The grains usually met
I INCH with are of a yellow colour. Letheby gives the following, as showing the
Fig. 51. composition of Indian-corn meal :
Indian-corn is largely eaten all over the Nitrogenous matter.
world, but more especially in tropical counCarbo-hydrates
tries, Fatty matter
81 Saline matter
The ration for a Kafir servant is 3 pints Water
140 of Indian-corn meal per day, and on this 100.0 scanty allowance-for he gets little else be
manages to keep in good health. Indian-oru A recent examination of the average Indian- has since 1846—the potato-famine year-been corn flour of the shops, made by Mr. H. C. largely used in Ireland. It is stirred into Bartlett, gave the following results :
boiling water or boiling milk, and formed into à sort of hasty-pudding, or thick porridge, no exhilaration, and rather absence of thought, and thus eaten.
and utter indifference to external things, than Throughout Mexico it forms the staple food, excitement or hallucinations. and is cooked by baking into cakes. Indian-corn, being deficient in gluten, does
Infants, Diet of — Carefully-collected not make good bread. Its flavour is harsh statistics, allied to general observation and and peculiar. A weak solution of caustic particular experiments, have conclusively potash removes this unpleasantness; but it proved that, as a food for young infants, also deprives it of much of its nitrogenous nothing has yet been found which can take matter, and so renders it less nutritious than the place of milk. before. This is the foundation of the process Diseases of Infancy and Childhood,” says :
Dr. West, in his valuable “ Lectures on the for preparing the articles extensively sold under the names of Oswego, Maizena, and form towards it a mother's part, or who by
“The infant whose mother refuses to perCorn-flour. As a mere adjuvant, or auxiliary, prepared
accident, disease, or death is deprived of the Indian-corn may be of value, but mothers and
food that nature destined for it, too often nurses should be earnestly cautioned against
languishes and dies. Such children you may injudiciously giving it to infants. See INFANTS,
see with no fat to give plumpness to their DIET OF.
limbs, no red particles in their blood to im
part a healthy hue to their skin, their face Indian Hemp-The dried flowering tops wearing in infancy the lineaments of age, of the female plants of Cannabis sativa, Linn. their voice a constant wail, their whole aspect (natural order Urticacece.) For medicinal use an embodiment of woe. But give to such that which is grown in India, and from which children the food that nature destined for the resin has not been removed, is alone to be them, and if the remedy do not come too late to employed.
save them, the mournful cry will cease, the face The parts employed in Asia for the purposes will assume look of content, by degrees the of intoxication are the herb or leaves, and the features of infancy will disclose themselves, resin. Indian hemp contains a resin (canna- the limbs will grow round, the skin pure red bine) soluble in alcohol and ether, but precipi- and white, and when at length we hear the tated by water; to this resin the plant owes merry laugh of babyhood, it seems almost as its active properties. The other principles if the little sufferer of some weeks before which have been separated are gum, extrac- must have been a changeling, and this the real tive, and an ethereal oil.
child brought back from fairyland.” Indian hemp produces a peculiar kind of Those who have visited the wretched homes intoxication, with hallucinations of a pleasing of women employed at factories, or of the perkind. It is said to act as an aphrodisiac, and nicious baby-farmers, will be able to endorse to augment the appetite for food. It is much fully Dr. West's words. used in the East, and preparations of it are
Milk- and it is the mother's milk to which sold under the name of “Hashish Bhang,” we now particularly refer - contains the "Gunjab," &c. “Gunjab-smoking,” says Dr. principles required for the growth and Chevers, " is ascertained to be the cause of a
nourishment of the child, and contains them very large proportion of the cases of acute in such a form as to be easily assimilated. mania admitted to the native lunatic asylum For the first few months but little saliva is of Bengal."
secreted ; the teeth do not appear for some As an intoxicant it is certainly not used to time; and the digestive organs of the child any extent in England, and as a medicine it are so extremely susceptible of derangement has much disappointed practitioners. Dr. that it is necessary even for the mother to Froumuller suggests that the drug contains exercise the greatest caution over what she fome ethereal ingredient which is dissipated herself eats. All this tends to show that the in the voyage from India; for he has seen in digestive capacity is extremely feeble-nay, that country marked effects from half a grain often, until after the eighth month, absolutely of the extract or even less, so that he had incapable of assimilating anything but milk. been accustomed to consider a grain and a half
When from an unnatural objection on a large dose; while in England he had found the part of the mother, from disease, from it necessary to give ten, twelve, or more death, or any other cause, the child does not grains to produce the desired effect.
receive the aliment prepared and elaborated The present writer has seen it produce in by nature for its sustenance, then, unEngland, when taken in large doses for the doubtedly, the nearest approach to the actual purpose of experiment, a sleepy, stupid state food given in the milk of the parent is the of drunkenness. There was certainly little or milk furnished by another woman.