ir/I./.fAM X/EMENS, F.R.S. 193 



five years ago to the effect of superadding to the simple play of 

 .so jiu nips the compressing and the re-expanding pump 

 an intercli;ui'_ror of temperature. That suggestion, as it presented 

 to him, was published only in a provisional specification 

 of a patent which had never been specified finally ; but more 

 thiiii that had been accomplished, and perhaps it might interest 

 the members to know exactly what had been done. Dr. Gorrie, 

 an American, had patented and brought to England a certain 

 scheme, which had been taken up by Mr. Wollastou Blake and a 

 fr\\ other gentlemen in London, who erected plant which was 

 perfect in all its details. The engine had a 25-inch cylinder and 

 5 feet stroke ; the compressing and re-expanding pumps were made 

 by James Watt & Co., and had been erected somewhere in the 

 north of London ; but when it came to be tried it was impossible 

 to get a depression of temperature exceeding 20 Fahrenheit. That 

 being the case, after several ineffectual attempts to improve the 

 result, he was asked to examine the machine and report to the 

 proprietors. He had lost sight of the report, but Mr. Wollaston 

 Blake had sent him a copy with the drawings, and suggestions 

 which ho had made for improving the efficiency of the engine, and 



lese would be appended to his remarks (see p. 195 et seq.~) The 



eport was of some interest, as it went very fully into the principles 

 underlying the question of refrigeration, and the causes of the 

 ion-realisation of those results which should have been effected. 

 It seemed curious that, from the & priori examination and calcula- 

 tions which he made, he had come to the conclusion that the 



jmperature could not be depressed more than 20 by the machine, 

 that when that reduction of temperature was reached the loss of 

 affect would exactly balance the beneficial result; and the actual trial 



jrroborated that statement. The author had. perhaps, hardly given 

 lira credit for the labour which he had spent upon the subject. He 



id not only devised the temperature interchanges, which was the 

 most essential feature in the whole process, and without which no 

 ufficient results could be obtained, but he had fully recognised 

 the antagonistic effect of aqueous vapour in the air dealt with. 



"he loss of effect " by throttled passages " he had given at 



LO'08 HP. That required some explanation. Dr. Gorrie evidently 



wished to avail himself of the expansive force of the compressed 



and cooled gases before they were discharged ag lin ; but he did 



VOL. i. o 



