Negretti & Zambra&rsquos Second Patent Mercurial Minimum Thermometer
In this thermometer a principle is used that has been long known to scientific men, viz. the affinity of mercury for platinum. If mercury be placed in contact with platinum under ordinary circumstances, no effect will take place; but if the mercury is once made to attack the platinum, the amalgamation is permanent and the contact perfect, so much so, that the principle was made use of in constructing standard barometers. A ring of platinum was fused round the end of the tube, dipping into
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Fig. 59.
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Directions for using.—Having suspended the thermometer in a horizontal position, the mercury is made to stand in exact contact with the platinum plug by slightly elevating the bulb end of the instrument. The thermometer is now ready for observation. On a decrease of temperature, the mercury will endeavour to contract first from the easier passage, viz. behind the bulb; but in consequence of the adhesion of the mercury to the platinum, it cannot recede from here, it is therefore forced to contract from the indicating tube, and will continue to do so as long as the temperature decreases; and as no indices are employed in this thermometer, the extreme end of the mercurial column will show “how cold it has been.” On an increase of temperature the mercury will glide over the platinum plug and expand by the easier passage into the supplementary chamber, and there remain until a decrease of temperature again takes place, when the mercury that had gone into the supplementary chamber will be the first to recede, until it reaches the platinum plug, its further progress being arrested; it will then fall in the indicating tube, and there remain until re-set.
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Ebullition
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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 filled with mercury, inverted in the usual manner, then allowed to float,... Measurement Of Heights By The Aneroid
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Alcohol does not expand equally for equal increments of heat, consequently errors are likely to exist in the scale indications unless the graduations are very accurately—not necessarily equally—made. On this account, as well as from t... Metallic Barometer
<p>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 construction of metallic steam-pressure gauges. We are here, however, only ... Method Of Calculating Heights By The Barometer
The pressure of the atmosphere being measured by the barometer, it is evident that as the instrument is carried up a high mountain or elevated in a balloon, the length of the column must decrease as the atmospheric pressure decreases, in consequenc... Method Of Calculating Heights From Observations With The Mountain Thermometer
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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 generation of a substance to which the term ozone has been given, on a... Negretti & Zambra&rsquos Second Patent Mercurial Minimum Thermometer
In this thermometer a principle is used that has been long known to scientific men, viz. the affinity of mercury for platinum. If mercury be placed in contact with platinum under ordinary circumstances, no effect will take place; but if the mercury... Negretti And Zambra&rsquos Farmer&rsquos Barometer And Domestic Weather-glass
<p>It is a well-known fact that the barometer is as much, or even more affected by a change of wind as it is by rain; and the objection raised against a simple barometer reading, as leaving the observer in doubt whether to expect wind or rain, is remo... Negretti And Zambra&rsquos Patent Maximum Thermometer
consists of a glass tube containing mercury fitted on an engraved scale, as shown in fig. 54. The part of the thermometer tube above the mercury is entirely free from air; and at the point A in the bend above the bulb, is inserted and fixed with th... Newman&rsquos Mountain Barometer
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A maximum thermometer, better perhaps in its action than Rutherford’s, has been suggested by Professor John Phillips, of Oxford. A small portion of air is introduced into an ordinary thermometer, so as to cut off about half an inch of the merc... Position For Rain-gauge &c
Rain gauges should be placed on the ground, in any position exposed to a free fall of rain, snow, or hail, where neither walls, buildings, nor trees shelter or cause eddies of wind. They should be supported by a frame, or other means, to prevent the... Pouillet&rsquos Pyrheliometer
<div>Fig. 67.<br> <img src="/images/fig67.jpg" alt=""></div> <p><br> This instrument is composed of a shallow cylinder of steel, <em>A</em>, fig. 67, which is filled with mercury. Into the cylinder a thermometer, <em>D</em>, is introduced, the ste... Precautions To Ensure Correct Graduation
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If some mercury, or any other fluid, be poured into a tube of glass, bent in the form of <strong>∪</strong>, and open at both ends, it will rise to the same height in both limbs, the tube being held vertically. If mercury be poured in first, an... Principle Of The Barometer
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<div>Fig. 78.<br> <img src="/images/fig78.jpg" alt=""></div> <p><br> <p>(Fig. 78) consists of a tube, <em>C</em>, made of silver, very thin, and perfectly polished; the tube is larger at one end than the other, the large part being 1·8 inches i... Robinson&rsquos Anemometer
<em>Dr. Robinson</em>, of Armagh, is the inventor of a very successful anemometer, which determines the horizontal velocity of the wind. It was first used in 1850, in the meteorological and tidal observations made on the coast of Ireland under the d... Rules For Foretelling The Weather
<p><br> A RISING BAROMETER.</p> <div> <p>A “Rapid” rise indicates unsettled weather.</p> <p>A “Gradual” rise indicates settled weather.</p> <p>A “Rise,” with dry air, and cold increasing in summer, indicat... Self-compensating Standard Barometer
<p>This barometer has been suggested to Messrs. Negretti and Zambra by Wentworth Erk, Esq. It consists of a regular barometer; but attached to the vernier is a double rack worked with one pinion, so that in setting or adjusting the vernier in one posi... Self-registering Rain-gauge
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<p>In a small box, 8 in. by 8 in. by 4 in., a complete set of meteorological instruments have been packed. The lid of the box, by an ingenious arrangement, is made to take off and hang up; on it are permanently fixed for observation, a maximum and min... 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
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<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...