494 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



• Mr. Rowell stated that he did not know of any book which 

 contained a definite account of the use of steam by expansion. 



Mr. Dibben said he had every facility for seeing those experi- 

 ments which are now making, and from what he has seen he has 

 come to the conclusion that Marriott's law is true. He stated 

 that the great loss in engines was the connection or conduction 

 of heat from the cylinder during the exhaust. Theory and prac- 

 tice, in his opinion, agreed together. 



Mr. Rowell. — The theoretical law gives an advantage of 280 

 per cent, by using heat cut off at one-eighth. We are not assail- 

 ing Marriott's law, but merely propose to see what the total re- 

 sult of expansion is. 



Mr. Seely thought that no weight should be placed on the 

 statements of the gentlemen, as they had nothing new to offer on 

 the subject. He referred them to Cook's Medical Physics, and 

 stated that he did not think the model used by the committee was 

 of much utility, as it required men of very great ingenuity to 

 understand the working of it. 



Mr. Hedrick sympathized with the men who were making 

 those experiments. He thought the advantages of the cut-oflf 

 were not so great as were allowed to it. The losses by the various 

 frictions, conductions, connections, &c., was what they wanted to 

 find out. By comparing them with the "cut-off" and the "non- 

 cut-off" they would be able to find the difi'erence. 



Mr. Seeley said he appreciated the value of these experiments 

 on real steam engines, but did not upon the apparatus on which 

 they were now making them. 



The Chairman inquired if it was attempted to be shown that 

 there was little or no gain by the cut-off? 



Mr. Garvey was of the opinion that those experiments, as phi- 

 losophical experiments, were greatly in error. The less parts 

 there are to any piece of mechanism the less loss of power. In 

 this aspect alone the cut-ofi' was defective, but when properly 

 applied its advantages have been abundantly established. 



Mr. Hedrick moved that the subject stand over until the first 

 of November. The motion was seconded and carried. 



The Chairman wished to know if there was any law on the 

 subject of adhesion. He stated that some experiments are now 

 making on a raihvaj^ by three engines on a wet rail, one working 

 without the sand box, and the other two with it, and that the 

 one working without the sand box was doing very well. 



