Thermometric Substances
Thermometers for meteorological and domestic purposes are constructed with liquids, and generally either mercury or alcohol, because their alterations of volume for the same change of temperature are greater than those of solids; while being more manageable, they are preferred to gases. Mercury is of all substances the best adapted for thermometric purposes, as it maintains the liquid state through a great alteration of heat, has a more equable co-efficient of expansion than any other fluid, and is peculiarly sensitive to changes of temperature. The temperature of solidification of mercury, according to Fahrenheit’s scale of temperature, is -40°; and its temperature of ebullition is about 600°. Sulphuric ether, nitric acid, oil of sassafras, and other limpid fluids, have been employed for thermometers.
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Small Size Aneroids
The patent for the Aneroid having expired, Admiral FitzRoy urged upon Messrs. Negretti & Zambra the desirability of reducing the size at which it had hitherto been made, as well as of improving its mechanical arrangement, and compensation for te... Solar And Terrestrial Radiation Considered
The surface of the earth absorbs the heat of the sun during the day, and radiates heat into space during the night. The envelope of gases and vapour, which we call the atmosphere, exerts highly important functions upon these processes. Thanks to th... Solar Radiation Thermometer
“As the interchange of heat between two bodies by radiation depends upon the relative temperature which they respectively possess, the earth, by the rays transmitted from the sun during the day, must be continually gaining an accession of heat... Standard Barometer
<p>Fig. 3 represents a Standard Barometer on Fortin’s principle. The barometer tube is enclosed and protected by a tube of brass extending throughout its whole length; the upper portion of the brass tube has two longitudinal openings opposite ea... Standard Syphon Barometer
<p>Fig. 24 represents the most accurate form of the Gay Lussac barometer. The short limb is closed at the top, after the mercury is introduced, and a small lateral), and here illustrated (fig. 25). Fig. 25.<br> <img src="/images/fig25.jpg" alt=""> ... Standard Thermometer
<div>Fig. 36<br> <img src="/images/fig36.jpg" alt=""><br> </div> <p>The peculiarities in the construction of thermometers will be best understood by describing the manufacture of a <em>Standard Thermometer</em>, which is one of the most accurate m... Sympiesometer
<div>Fig. 32.<br> <img src="/images/fig32.jpg" alt=""></div> <p>Nevertheless the instrument now about to be described, depending upon similar principles, but scientifically constructed and graduated, is a very useful and valuable substitute for the... Syphon With Photographic Registration
A continuous self-registering barometer has been constructed, in which photography is employed. Those who may wish to adopt a similar apparatus, or thoroughly to understand the arrangements and mode of observation, should consult the detailed descr... Temperature Is The Energy With Which Heat Affects Our Sensation Of Feeling
<p>Bodies are said to possess the same temperature, when the amounts of heat which they respectively contain act outwardly with the same intensity of transfer or absorption, producing in the one case the sensation of warmth, in the other that of coldn... The Barometer Vernier
The <em>vernier</em>, an invaluable contrivance for measuring small spaces, was invented by Peter Vernier, about the year 1630. The barometer scale is divided into inches and tenths. The vernier enables us to accurately subdivide the tenths into hun... The Common Formthe Barometer Is Of Great Use To The Mariner Who By Using It As A &ldquoweather Glass&rdquo Is Enabled To Fores
<p>Other forms of barometer (to be immediately described) have superseded this in the British Marine, but the French still give the preference to the wooden frames. They think the barometer can be more securely mounted in wood, is more portable, and l... The Fitzroy Marine Barometer
<p>Admiral FitzRoy deemed it desirable to construct a form of barometer as practically useful as possible for marine purposes. One that should be less delicate in structure than the Kew barometer, and not so finely graduated. One that could be set at ... The Kew Marine Barometer
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 observations at sea.</p> <p>The materials employed in its construction are mer... The Scale
The two fixed points having been determined, it is necessary to apply the scale. The thermometers in general use in the United Kingdom, the British Colonies, and North America are constructed with Fahrenheit’s scale. Fahrenheit was a philosoph... The Syphon Tube Mountain Barometer On Gay Lussac&rsquos Principle
The Syphon Tube Mountain Barometer, on Gay Lussac’s principle is fixed in a metallic tubular frame, forms a simple and light travelling instrument. The graduations are made upon the frame, and it is suspended for reading by a ring at the top, fr... The Vane
<div>Fig. 86.<br> <img src="/images/fig86.jpg" alt=""></div> <p><br> 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, s... The Words On The Scale
The following words are usually engraved on the scales of these barometers, although they are not now considered of so much importance as formerly:—</p> <table summary="table" border="0" cellpadding="0" cellspacing="5"> <tbody> <tr> ... Thermometer Screen For Use At Sea
This screen, or shade, was designed by Admiral FitzRoy, and has been in use for several years on board H.M. vessels and many merchant-ships. It is about twenty-four inches long by twelve wide and eight deep; having lattice-work sides, door, and bot... Thermometers For Engineers
<em>1st. Salinometer.</em>—Under the circumstances at which fresh water boils at 212°, sea water boils at 213°·2. The boiling temperature is raised by the chemical solution of any substance in the water, and the more with the increas... Thermometric Substances
Thermometers for meteorological and domestic purposes are constructed with liquids, and generally either mercury or alcohol, because their alterations of volume for the same change of temperature are greater than those of solids; while being more ma... Thomson&rsquos Electrometer
Professor W. Thomson, of Glasgow, has devised an atmospheric electrometer, which is likely to become eminently successful, in the hands of skilful observers. It is mainly a torsion balance combined with a Leyden-jar. The index is an aluminium needle... Trials Of The Fitzroy Marine Barometer Under Fire Of Guns
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. <em>Excellent</em>; and under all the circumstances, they withstood the c... Use Of The Barometer In Estimating The Height Of Tides
The pressure of the atmosphere affects the height of the tide, the water being in general higher as the barometer is lower. The expressions of seamen, that “frost nips the tide,” and “fog nips the tide,” are explained by the ... Use Of The Barometer In The Management Of Mines
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 released from the coal, the atmospheric pressure tends to drive them... Vacuum Solar Radiation Thermometer
In order that the heat absorbed by the blackened bulb of the solar radiation thermometer may not in part be carried off by the currents of air which would come into contact with it, the instrument has been improved by Messrs. Negretti and Zambra int... Varieties Of Thermometers
<p>Fig. 37 is an illustration of boxwood scale thermometers for general use and common purposes.</p> <p>Fig. 38, Negretti and Zambra’s Travelling Thermometer; it is fixed in a plated metal (silver or otherwise) case, similar to a pencil-case, an... Whewell&rsquos Anemometer
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 follows:—</p> <p>A horizontal brass plate is attached to a ver... Athrioscope
The celebrated experimental philosopher, Sir John Leslie, was the inventor of this instrument, the purpose of which is to give a comparative idea of the radiation proceeding from the surface of the earth towards the sky. It consists, as represented... Public Barometers
<p>Since the increased attention paid to the signs of forthcoming weather of late years, and the good which has resulted therefrom to farmers, gardeners, civil engineers, miners, fishermen, and mariners generally, by forewarning of impending wet or sto...