942 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



It is foreign to my purpose to quote tlie tables and experiments relat- 

 ing to the differences in temperature between tlie air and the water at 

 their influx and egress; but a crucial experiment which he performed 

 was conclusive and interesting: "During an experiment of an hour's du- 

 ration the water of injection, instead of being supplied, as usual, by the 

 city hydrant, was taken from and returned to a butt of about 130 gallons 

 capacity, containing about 1,100 pounds of water. At the commence- 

 ment of the experiment the temperature of the water was 77° Fahr. (the 

 atmosphere being 79o Fahr.); at the end it was 112o Fahr., the engine 

 working twenty revolutions a minute. The quantity of ice which'^the 

 heat thus disengaged would melt is equal to (1100 x 32-^ 110=) 275 

 pounds; or for 24 hours, 6,600 pounds. There was but very little dimi- 

 nution in the rate at which the temperature of the water was increased. 



"The quantity of heat which the condensed air in its expansion is ca- 

 pable of absorbing, or, in other words, the quantity of ice it is capable 

 of producing, proves that there has been no material error of observation 

 or calculation. 



" The quantity of heat generated by compressing air to half its volume 

 is sufficient to elevate the temperature of an equal weight of water 74^ 

 Fahr., and of its own body 277° Fahr. When it was reduced to one- 

 fourth of its volume, the increase of heat became, for water, 105° Fahr., 

 and for air, 395° Fahr.; and when condensed to one-eighth of its original 

 volume, the heat was, for water, 125°, and for air 472° Fahr. 



"According to these observations and deductions, while the densities 

 of air increased in the geometrical progression 2, 4, 8, the heat evolved 

 corresponded nearly to the arithmetical series 3, 4, 5. But the ratio in 

 the diflerences of temperature between the assigned densities foUows a 

 very different rate of progression from either : thus, for the densities 

 2, 4, 8, atmospheric pressure, the corresponding differences of heat 

 evolved were, in the decreasing number, nearly (277, 118, 80) 3.5, 1.5, 1." 



I need not further refer to Mr. C. W. Siemens's idea of compressing air 

 and expanding it in an engine as noticed elsewhere. Mr. Alexander 

 Carnegie Kirk was the first and most successful inventor of a practical 

 air-machine for making ice. He \^ished to supersede an ether-machine 

 at the Bathgate Paraffin Works, owing to its being too small and dan- 

 gerous. He had to cool the oils to a temperature of from 35° to 40^ 

 Fahr., to crystallize the paraffin. On his first trial air was compressed 

 into a receiver and allowed to expand by dri\iug a small engine— a plan 

 which had been proposed and tried— but it offered little encouragement. 

 The next trial was with an app^^atus similar to Stirling's air-engine, 

 with which, after many modifications, mercury was frozen. Mr. Kirk 

 designed a machine, patented on the 25th April, 1862, for the applica- 

 tion and use to and in the production of cold of a vessel containing air 

 or other elastic fluid or gas alternately in a state of compressioiraud 

 expansion, and provided with a piston and regenerator. On the piston 

 being moved to one end of the vessel, the enclosed air may pass freely 

 to the other end, giving out its heat to or absorbing heat from the regenera 



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