In using mercury thermometers, it is best, as in the apparatus figured, to work on a large scale (4-in.
Van Rysselberghe, but the later, put forward in 1867, included metallic thermometers and was less successful.
C. Mitchell, under Tait's direction, repeated the experiments with the same bar nickel-plated, correcting the thermometers for stem-exposure, and also varying the conditions by cooling one end, so as to obtain a steeper gradient.
3 were obtained from the readings of a number of platinum thermometers buried in undisturbed soil in horizontal positions at M`Gill College, Montreal.
Is best avoided by employing platinum thermometers buried horizontally.
Flows through the spiral coolers N and M, and finally through the box H, where it is well mixed before passing the outflow thermometer P. As soon as a steady state is reached, the difference of temperature between the outflow and inflow thermometers, multiplied by the current of water in grammes per minute gives the heat per minute supplied by combustion.
His thermometers were subsequently corrected to the Paris scale by A.
Pernet, Extended From O° To 100° C., And Appears To Have Attained As High A Degree Of Excellence As It Is Possible To Reach By The Employment Of Mercury Thermometers In Conjunction With The Method Of Mixture.
They are also partly caused by the large uncertainties of the corrections, especially those of the mercury thermometers under the peculiar conditions of the experiment.
The gradient near the entrance to the calorimeter was deduced from observations with five thermometers at suitable intervals along the bar.
An additional difficulty arises in the case of observations made with long mercury thermometers buried in vertical holes, that the correction for the expansion of the liquid in the long stems is uncertain, and that the holes may serve as channels for percolation, and thus lead to exceptionally high values.
The amplitudes and phases of the temperature waves at different points are observed by taking readings of the thermometers at regular intervals.
No allowance was made for the variation of density with temperature, or for the variation of the distance between the thermometers, owing to the expansion of the bar.
000 Per 1° C. His Thermometers Were Compared With A Mercury Thermometer Standardized In Paris, And With A Platinum Thermometer Standardized By Griffiths.
In Spite Of The Large Corrections The Results Were Extremely Consistent, And The Value Of The Temperature Coefficient Of The Diminution Of The Specific Heat Of Water, Deduced From The Observed Variation In The Rate Of Rise At Different Points Of The Range 15° To 25°, Agreed With The Value Subsequently Deduced From Rowland'S Experiments Over The Same Range, When His Thermometers Were Reduced To The Same Scale.
9, Is Heated By A Steady Electric Current During Its Passage Through The Tube, And The Difference Of Temperature Do Between The Inflowing And The Outflowing Liquid Is Measured By A Single Reading With A Delicate Pair Of Differential Platinum Thermometers At A And B.
Stirring Is Effected By Causing The Water To Circulate Spirally Round The Bulbs Of The Thermometers And The Heating Conductor As Indicated In The Figure.
Among Amesbury's manufactures are hats, cotton goods, carriages, automobile bodies, carriage and automobile lamps, thermometers, brass castings and 'motor boats.
The original intention was to push the experiments to a pressure equivalent to thirty atmospheres, but owing to the signs of failure exhibited by the boiler the limit actually reached was twenty-four atmospheres, at which pressure the thermometers indicated a temperature of about 224 0 C. In his last paper, published posthumously in 1838, Dulong gave an account of experiments made to determine the heat disengaged in the combination of various simple and compound bodies, together with a description of the calorimeter he employed.
Trans., 1776) contains remarks on the precautions necessary in making and using thermometers, a subject which is continued in the following year in a report signed by him and six others.
Observations for temperature have been taken for many years at the stations of the Indo-European Telegraph and for a few years at the British consulate in Meshed, and the monthly and annual means shown in the following table have been derived from the indications of maximum and minimum thermometers in degrees Fahrenheit.
Along the shores of the Caspian, particularly in Gilan and Mazandaran, and of the Persian Gulf from the mouth of the Shatt el Arab down to Bander Abbasi, the air during a great part of the year contains much moisturedry- and wet-bulb thermometers at times indicating the same temperatureand at nights there are heavy falls of dew.
The paddle was driven by weights, and the temperature of the water was observed by thermometers which could indicate 2 kuth of a degree Fahrenheit.
The white line of enamel, which is seen in some thermometers behind the bore, is introduced before the mass of glass is pulled out.
In modern thermometry instruments of extreme accuracy are required, and researches have been made, especially in Germany and France, to ascertain the causes of variability in mercurial thermometers, and how such variability is to be removed or reduced.
In all mercurial thermometers there is a slight depression of the ice-point after exposure to high temperatures; it is also not uncommon to find that the readings of two thermometers between the iceand boiling-points fail to agree at any intermediate temperature, although the iceand boiling-points of both have been determined together with perfect accuracy, and the intervening spaces have been equally divided.
The measurement of temperature in the depths, unless a high-speed waterbottle be used, involves stopping the ship and employing thermometers of special construction.
All thermometers sunk into deep water must be protected against the enormous pressure to which they are exposed.
If the plate is thin, it is necessary to measure the thickness with great care, and it is necessary to assume that the temperatures of the surfaces are the same as those of the media with which they are in contact, since there is no room to insert thermometers in the plate itself.
The actual tempera ture of the metal itself can then be observed by inserting thermometers or thermo-couples at measured distances from the centre.
The chief difficulty in this method lay in determining the effective distances of the bulbs of the thermometers from the axis of the cylinder, and in ensuring uniformity of flow of heat along different radii.
And 12 in., between the thermometers compared.
Noll employed mercury thermometers, but as he worked over a small range with vapour baths, it is probable that he did not experience any trouble from immersion corrections.
He states that the deviations from the formula were " quite within the limits of error introduced by the alteration of the resistance of the circuit with rise of temperature, the deviations of the mercury thermometers from the absolute scale, and the non-correction of the indications of the thermometer for the long column of mercury not immersed in the hot oil round the junctions."
Calculating the actual, societal costs of fatty foods, alcohol, cars, pet ownership, mercury thermometers, air conditioning, solar panels, razor blades, jogging shoes, and ten thousand other things, and incorporating those costs in the prices as taxes would lead to a vastly more efficient allocation of resources.
From 1879 to 1888 he was engaged on difficult experimental investigations, which began with an inquiry into the corrections required, owing to the great pressures to which the instruments had been subjected, in the readings of the thermometers employed by the "Challenger" expedition for observing deep-sea temperatures, and which were extended to include the compressibility of water, glass and mercury.
The oil-cup is supported in a bath or heating-vessel, consisting of two flat-bottomed copper cylinders, to contain water, heated by a spirit lamp, and provided with an air-space between the water-vessel and the oil-cup. Thermometers are placed in both oil-cup and waterbath, the temperature of the latter being raised to 130° at the commencement of the test, while the oil is put in at about 60° F.
Special glasses for thermometers, and other special glasses.
Special glasses have therefore been produced by Tonnelot in France and at the Jena glassworks in Germany expressly for the manufacture of thermometers for accurate physical measurements; the analyses of these are shown in Table III.
Since 1870 thermometers on this principle have been in use for regular observations at German coast and light-ship stations.
At the time of the construction of the imperial standards in 1844, Sheepshanks's Fahrenheit thermometers were used; but it is difficult to say now what the true temperature then, of 62° F., may have been as compared with 62° F., or 16.667° C., of the present normal hydrogen scale.