On the temperature of steam and its corresponding pressure

Abstracts of the Papers Communicated to the Royal Society of London ◽

10.1098/rspl.1843.0235 ◽

1851 ◽

Vol 5 ◽

pp. 941-942

Keyword(s):

Fourth Power ◽

Steam Boiler ◽

Foregoing Case ◽

Limited Space ◽

Academy Of Sciences ◽

True Measure

The author states that it is intended in this paper to propose a simple law to determine the pressure of steam corresponding to any given temperature, irrespectively of experiment , taking as the sole datum, that the vaporizing point of water under a given pressure is 100 degrees, that number being taken to correspond with the scale of Celsius; also to construct formulæ in accordance therewith; and afterwards to compare their results with the actual experiments of the Academy of Sciences of Paris. He further states that the rationale of the subsequent formulae is expressed as follows. Let it be conceived that a given quantity of water is vaporized under the condition that the pressure thereon is increased in the same ratio that the volume is increased, or that at intervals of temperature 1, 2, 8, &c. the volume is increased the same or in equal proportions; the temperature of the volume will be increased exactly as the square of the temperature indicated by the thermometer, supposing the instrument to be a true measure of temperature, and as the square of the volume ; and the same of the pressure . Steam being generated from an indefinite quantity of water and confined within a limited space, as in the usual boiler, he considers the foregoing case is reversed ; for the volume being constant, the action of the fire is entirely exerted in producing increased elastic tension of the vapour; therefore the temperature of the steam at the interval 1 to 2 degrees is increased inversely in the duplicate ratio of the ratio in the case first described; that is, the pressure is increased directly at the square of the square, or fourth power of the temperature; whence the following law. The pressure of steam generated in the usual steam-boiler is directly proportional to the fourth power of its temperature, when measured by a true scale.

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On the water barometer erected in the hall of the Royal Society

Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London ◽

10.1098/rspl.1830.0079 ◽

1837 ◽

Vol 3 ◽

pp. 134-136

Keyword(s):

Royal Society ◽

Present Situation ◽

Atmospheric Tides ◽

Steam Boiler ◽

Periodic Oscillations ◽

French Academy ◽

Different Temperatures ◽

History Of ◽

Additional Support ◽

Academy Of Sciences

The author having long considered that a good series of observations with a water barometer would be of great value as throwing light upon the theory of atmospheric tides, of the horary and other periodic oscillations of the barometer, and of the tension of vapourat different temperatures, was desirous of learning whether any such series of observations had ever been made. But he could meet with none having any pretensions to accuracy ; for neither those of Otto Guericke, in whose hands the water barometer was merely a philosophical toy, nor the cursory notices of the experiments of Mariotte upon this subject contained in the History of the French Academy of Sciences, can be considered as having any such claim. The difficulties which opposed the construction of a perfect instrument of this kind long appeared to be insurmountable; but the author at length proposed a plan for this purpose, which, having been approved of by the late Meteorological Committee of the Royal Society, was ordered by the President and Council to be carried into execution. The author then enters fully into the details of the methods he employed for constructing the whole of the apparatus, and for placing in its present situation in the centre of the winding staircase conducting to the apartments of the Royal Society. The tube was very skilfully made by Messrs. Pellattand Co. at the Falcon Glass-house. It was 40 feet long, and one inch in diameter at its lower end; and so nearly cylindrical, throughout its whole extent, as to diminish only by two tenths of an inch at its upper end. A second tube of the same dimensions was also made as a provision in reserve against any accident happening to the first. These tubes were both securely lodged in a square case by means of proper supports. A small thermometer with a platina scale, was introduced into the upper end of the tube. An external collar of glass was united to that end by heating it. This was done with a view of giving it additional support, and of preventing it from slipping. This end of the tube was then drawn out into a fine tube ready for sealing with the blowpipe; and a small stopcock was fitted on to it. The cistern of the barometer was formed by a small copper steam boiler, 18 inches long, 11 wide, and 10 deep, capable of being closed by a cock, and having at the bottom a small receptacle for holding the lower end of the tube, so as to allow of the water in the cistern being withdrawn, without dis turbing that contained in the tube.

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