STEAM, 



333 



instrument maker in the university of Glasgow, 

 and considering the simplicity of the apparatus 

 with which he conducted his experiments, the 

 results he obtained are remarkable for their accu- 

 racy. The range of his experiments, extended from 

 55 to 272 Fahrenheit. 



Dissatisfied with his own experiments, in the re- 

 sults of which he observed irregularities which he 

 could not explain, Mr Watt, in the year 1796, re- 

 quested Mr Southern to try them over again, and, 

 in fulfilling his requests, he was assisted by Mr 

 William Creighton. 



Mr Achard of the Royal Academy of Berlin, 

 published, in the Memoirs of 1782, a series of ex- 

 periments on the elasticity of steam, from the tem- 

 perature of 32 to that of 212. The following 

 are a few of the results, which are here compared 

 with those of Mr Watt and Mr Robison, (after- 

 wards Dr Robison) at this time a student at Glas- 

 gow, and subsequently the professor of Natural 

 Philosophy in the University of Edinburgh : 



168 

 189 



Achard. 



ElaitieiiiM. 

 Inchei. 



11-05 



18-5 



28.1 



Watt. 



ilalticitiei 

 Im-Iiei. 



11-24 

 18-45 

 2V88 



10-60 

 17-47 

 26-05 



The following results were obtained by Dr Ro- 

 bison : 



The next experiments on the elasticity of steam 

 were made by Bettancourt, who also made similar 

 experiments on the elasticity of the vapour of spirit 

 of wine, and he found it at all temperatures equal 

 to 2 times that of steam. The next set of ex- 

 periments on steam were made by Dr Dalton about 

 1800, with a degree of accuracy and care, which 

 gives them a high value. The following is a table 

 of his results. 



Dr Ure made various Experiments on the Elastii: 

 Force of Steam from 24 to 312, the following 

 results of which are given in inches of mercury : 



The next experiments on the elasticity of steam 

 were those of Mr Philip Taylor, at temperatures 

 from 212 to 320. But these do not differ so 

 materially from the foregoing as to require insertion. 



A very valuable set of experiments were made a 

 few years since, by M. Arago and other members 

 of the French Institute. The results contained in 

 the following table, given by them, were obtained 

 by direct experiment, from 1 to 24 atmospheres; all 

 above this were calculated by a formula, and can- 

 not, of course, be so much depended upon. 



The most recent experiments on the elastic force 

 of steam are those by a committee of the Franklin 

 Institute, appointed by the treasury directors of 

 the United States. The object of the committee 

 was to inquire into the causes of the explosion of 

 steam boilers, to investigate which they were re- 

 quested to make experiments on the properties of 

 steam, the expence of which was defrayed out of 

 the treasury of the United States. The appoint- 

 ment of this committee is highly honourable to the 

 government of the North American republic, and 

 has been rewarded by results of great advantage to 

 science, and highly creditable to the gentlemen who 

 conducted the experiments. We give here an ex- 

 tract from the report, as published in the Journal 

 of the Franklin Institute. The committee, deter- 

 mined to put the apparatus which was necessary 

 for other experiments, to the best use possible, in 

 determining the elastic force of steam, at different 

 temperatures; and accordingly great pains were 

 bestowed upon the graduation of the guage, the 

 regulation of the temperature of its parts, &c., the 

 comparison of the thermometers, the maintenance 

 of the scales at about the same temperature, &c. 

 The small size of the boiler, and the various open- 

 ings required to be made in it for the experiments 

 which were the immediate objects of the committee, 

 were unfavourable to the attainment of considerable 



