If some mercury, or any other fluid, be poured into a tube of glass, bent in the form of ∪, and open at both ends, it will rise to the same height in both limbs, the tube being h...
Fig. 29. Fig. 29 is an illustration of the mountain barometer known as Newman’s. The cistern consists of two separate compartments;—the top of the lower and the bottom of the upp...
The great difficulty to be overcome in Milne’s barometer, is to adjust the mechanism for obtaining registration so that the action of the striker upon the pointer should not in the...
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 cas...
Fig. 77. This instrument was invented about the year 1820, by Professor Daniel, the distinguished author of Meteorological Essays; and it entirely superseded all hygrometers depend...
The Dry and Wet Bulb Hygrometer, or Psychrometer, known also as Mason’s hygrometer (fig. 79), consists of two parallel thermometers, as nearly identical as possible, mounted on a w...
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...
The following words are usually engraved on the scales of these barometers, although they are not now considered of so much importance as formerly:— At 31 inches  Very dry. " 30...
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 reg...
The form of barometer so-called, is that recommended by the Congress of Brussels, held in 1853, for the purpose of devising a systematic plan of promoting meteorological observatio...
The French have imitated this form of barometer for coast service, and have translated Admiral FitzRoy’s indications for the scale as follows:— LA  LA HAUSSE  BAISSE INDIQUE. Â...
This instrument, the invention of M. Bourdon, has a great resemblance to the aneroid, but is much simpler in arrangement. The inventor has applied the same principle to the constru...
During the action of a powerful electric machine, and in the decomposition of water by the voltaic battery, a peculiar odour is perceptible, which is considered to arise from the g...
Mr. Follet Osler is the inventor of a self-recording apparatus which registers the direction and pressure of the wind, and the amount and duration of rain, upon the same sheet of p...
Fig. 52. This instrument is a special construction to meet the requirements of navigation. It consists of a carefully constructed thermometer divided on its stem to degrees, which...
A barometer designed by a gentleman named McNeild is on a directly opposite principle to the one just described. The tube is made to float on the mercury in the cistern. It is fill...
The general form and arrangement of this instrument is shown in fig. 60. A tube with large bore, a, has at the end a flat glass diaphragm formed by the abrupt junction of a small c...
The instruments devised for the purpose of ascertaining the humidity of the atmosphere are termed hygrometers. The earliest invented hygrometers were constructed of substances read...
Fig. 86. The instrument by which the wind’s direction is most generally noted, is the vane, or weather-cock, and all that need be said of it here is that the points north, east, so...
“In nearly all the barometers which had been employed at sea till recently the index correction varied through the range of scale readings, in proportion to the difference of capac...
70. Rutherford’s Maximum Thermometer.—The maximum thermometer, invented by Dr. John Rutherford, differs from an ordinary thermometer in having a small cylinder of steel, porcelai...
The inflammable and suffocating gases, known to coal-miners as fire-damp and choke-damp, are specifically heavier than air; and as they issue from the fissures of the mine, or are...
The general electrical condition of the atmosphere is positive in relation to the surface of the earth and ocean, becoming more and more positive as the altitude increases. When th...
73. Rutherford’s Alcohol Minimum Thermometer, fig. 55, consists of a glass tube, the bulb and part of the bore of which is filled with perfectly pure spirits of wine, in which move...
This apparatus, the invention of the celebrated Dr. W. Whewell, registers the horizontal motion of the air with the direction. Its mechanism may be described in general terms, as f...
Fig. 93. A glass tube having a large bulb at each extremity, and bent twice at right angles, as represented in figure 93, containing strong sulphuric acid tinged with carmine, and...
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 essentia...
Some of the first barometers made by Messrs. Negretti and Zambra on Admiral FitzRoy’s principle were severely tried under the heaviest naval gun firing, on board H.M.S. Excellent;...
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 seri...
;The line of danger, whether from the burning or lifting power of lightning, is the line of strong and obstructed currents of air, of the greatest aerial friction.” Trees, church s...