Description Of The Thermometer
The ordinary thermometer consists of a glass tube of very fine bore, having a bulb of thin glass at one extremity, and closed at the other. The bulb and part of the tube contains mercury; the rest of the tube is a vacuum, and affords space for the expansion of the liquid. This arrangement renders very perceptible the alterations in volume of the mercury due to changes of temperature. It is true, the glass expands and contracts also; but only by about one-twentieth of the extent of the mercury. Regarding the bulb, then, as unalterable in size, all the changes in the bulk of the fluid must take place in the tube, and be exhibited by the expansion and contraction of the column, which variations are made to measure changes of temperature.
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Displacement Of The Freezing Point
Either the prolonged effect of the atmospheric pressure upon the thin glass of the bulbs of thermometers, or the gradual restoration of the equilibrium of the particles of the glass after having been greatly disturbed by the operation of boiling the... Watch Aneroid
Subsequently the aneroid has been further reduced in size and it can now be had from an inch and a quarter to six inches in diameter. The smallest size can be enclosed in watch cases, fig. 35, or otherwise, so as to be adapted to the pocket. By a be... 2 Construction Of Barometers
In order that the instrument may be portable, it must be made a fixture and mounted on a support; and, further, to render it scientifically or even practically useful, many precautions are required in its construction. The following remarks apply to ... Admiral Fitzroy&rsquos Rain-gauge
A form of rain-gauge, very well adapted for expeditious observation at any time, has been designed by Admiral FitzRoy, and extensively employed by his observers. It is cylindrical in shape, with the funnel let into the top; and the rainfall is coll... Admiral Fitzroy&rsquos Scale Words
The directions given on the scales of these barometers were drawn up by Admiral FitzRoy, F.R.S. They appear to be founded on the following considerations:—</p> <p>Supposing a compass diagram, with the principal points laid down, the N.E. is ... Admiral Fitzroy&rsquos Words For The Scale
The graduation of inches and decimals are placed in this barometer on the right-hand side of the tube; and on a similar piece of porcelain, on the left-hand, are engraved, as legibly as they are expressed succinctly, the following words, of univers... Aneroids
<p>The beautiful and highly ingenious instrument called by the name <em>Aneroid</em>, is no less remarkable for the scientific principles of its construction and action, than for the nicety of its mechanism. It is a substitute, and perhaps the best of ... Atmospheric Electroscope
<div>Fig. 90.<br> <img src="/images/fig90.jpg" alt=""></div> <p><br> The simplest instrument for ascertaining at any time the electric condition of the atmosphere is an electroscope composed of two equal pieces of gold leaf, suspended from a brass... Barometer With Electrical Adjustment
<p>This barometer is useful to persons whose eyesight may be defective; and is capable of being read off to greater accuracy than ordinary barometers, as will be seen by the following description:—The barometer consists of an upright tube dippi... Baudin&rsquos Alcohol Minimum Thermometer
This instrument resembles Rutherford’s thermometer in appearance; its indications are given by the expansion and contraction of alcohol, and its minimum temperature is likewise registered by a glass index being pulled back and left behind by ... Beckley&rsquos Anemometer
Mr. R. Beckley, of the Kew Observatory, has devised a self-registering anemometer, which consists of three principal parts: Robinson’s cups for the determination of velocity; a double fan, or wind-mill governor, for obtaining the direction; an... Casella&rsquos Mercurial Minimum Thermometer
The general form and arrangement of this instrument is shown in fig. 60. A tube with large bore, <em>a</em>, has at the end a <em>flat glass diaphragm</em> formed by the abrupt junction of a small chamber, <em>b c</em>, the inlet to which at <em>b</... Causes Of Rain
When the invisible vapour which is diffused in the atmosphere becomes sufficiently cooled, it appears visible as mist or cloud, and a further reduction of temperature causes its precipitation as rain, hail, or snow. The cooling of the higher regions... Causes Which May Bring About A Fall Or A Rise In The Barometer
As heat produces rarefaction, a sudden rise of temperature in a distant quarter may affect the weight of the atmosphere over our heads, by producing an aerial current outwards, to supply the place of the lighter air which has moved from its former ... Chemical Weather Glass
This curious instrument appears to have been invented more than a hundred years ago, but the original maker is not known. It is simply a glass vial about ten inches long and three quarters of an inch in diameter, which is nearly filled, and hermetic... Daniel&rsquos Hygrometer
<div>Fig. 77.<br> <img src="/images/fig77.jpg" alt=""></div> <p>This instrument was invented about the year 1820, by Professor Daniel, the distinguished author of <em>Meteorological Essays</em>; and it entirely superseded all hygrometers depending ... Description Of The Thermometer
The ordinary thermometer consists of a glass tube of very fine bore, having a bulb of thin glass at one extremity, and closed at the other. The bulb and part of the tube contains mercury; the rest of the tube is a vacuum, and affords space for the ... Desirability Of Magnifying The Barometer Range
The limits within which the ordinary barometric column oscillates, do not exceed four inches for extreme range, while the ordinary range is confined to about two inches; hence it has often been felt that the public utility of the instrument would b... Dial Or Wheel Barometers
<p>The familiar household “Weather Glasses” are barometers on the syphon principle. The portions of the two limbs through which the mercury will rise and fall with the varying pressure of the atmosphere are made of precisely the same diame... Distribution And Effects Of Ozone
Mr. Glaisher has found that “the amount of ozone at stations of low elevation is small; at stations of high elevation, it is almost always present; and at other and intermediate stations, it is generally so. The presence and amount of ozone wo... Earth Thermometer
<p>The Earth Thermometer is for ascertaining the temperature of the soil at various depths. It is protected by a brass frame, pointed and strengthened at the end to facilitate insertion into the ground, as in fig. 51.</p> <div>Fig. 51.<br> <img src... Ebullition
The temperature at which a fluid <em>boils</em> is called the <em>boiling-point</em> of that particular fluid. It is different for different liquids; and, moreover, in the same liquid it varies with certain changes of circumstance. Thus the same liqu... Fishery Or Sea-coast Barometers
<div>Fig. 12.<br> <img src="/images/fig12.jpg" alt=""></div> <p><br> Fig. 12 gives a representation of these coast and fishery barometers. The frame is of solid oak, firmly screwed together. The scales are very legibly engraved on porcelain by Ne... Fortin&rsquos Barometer
Fortin’s plan of constructing a barometer cistern is shown in fig. 2. The cistern is formed of a glass cylinder, which allows of the level of the mercury within being seen. The bottom of the cylinder is made of sheep-skin or leather, like a ba... French Sea-coast Barometer
The French have imitated this form of barometer for coast service, and have translated Admiral FitzRoy’s indications for the scale as follows:—</p> <table summary="table" border="0" cellpadding="0" cellspacing="5"> <tbody> <tr> ... Fundamental Facts Regarding Atmospheric Electricity
The <em>general</em> electrical condition of the atmosphere is <em>positive</em> in relation to the surface of the earth and ocean, becoming more and more positive as the altitude increases. When the sky is overcast, and the clouds are moving in dif... Horticultural Minimum Thermometer
This instrument, represented in fig. 56, is a special construction of Rutherford’s minimum thermometer to meet the requirements of horticulturists. It is desirable, if not essential, that gardeners should have the means of ascertaining to what... Howard&rsquos Rain-gauge
It consists of a copper funnel, a stout glass or stone bottle, and a measuring glass. The bottle is to be placed upon the ground, with the funnel resting on its neck. A brass band or cylinder fixed upon the outer surface of the funnel envelops the n... Howson&rsquos Long Range Barometer
<div>Fig. 31.<br> <img src="/images/fig31.jpg" alt=""></div> <p><br> Very recently quite a novel design has been patented by Mr. Howson, for a long range barometer. The construction requires neither distortion of the tube, nor mechanism for conver... Hydrometer
<div>Fig. 96.<br> <img src="/images/fig96.jpg" alt=""></div> <div>Fig. 97.<br> <img src="/images/fig97.jpg" alt=""></div> <p><br> <p>A simple kind of hydrometer is very much used at sea, as “a sea-water test;” and as the observati... Hygrometric Substances
The instruments devised for the purpose of ascertaining the humidity of the atmosphere are termed <em>hygrometers</em>. The earliest invented hygrometers were constructed of substances readily acted upon by the vapour in the air, such as hair, grass... Importance Of Self-registering Thermometers
Heat being apparently the most effective agent in producing meteorological phenomena, the determination of the highest temperature of the day, and the lowest during the night, is a prime essential to enable an estimate of the climate of any place t... Instructions For The Sea-coast Barometer
The directions for fixing the barometer, and making it portable when it has to be removed, should be attended to carefully. The barometer should be suspended against a frame or piece of wood, so that light may be seen <em>through</em> the tube. Othe... Johnson&rsquos Metallic Deep-sea Thermometer
The objection to the employment of mercurial thermometers for ascertaining the temperature of the ocean at depths, arising from the compression of the bulbs, which was of such serious consequence previous to the modification made in the constructio...