S2G TRANSACTIONS OF THE AMEHICAN INSTITUTE. 



The Chairman added that for strings and pipes the law is the same. 

 When homogeneous and of the same diameter, the pitch of octaves is di- 

 rectly the same as the length. A string oi a given pitch, if halved, will 

 give a sound an octave higher — or if doubled in length a sovmd an octave 

 lower. 



The Best Mode of Producing Heat, 



The discussion of this subject was opened by Mr. Bartlett. There were 

 many ways of producing heat, by friction, compression, percussion, &c., but 

 there is only one approved mode, and that is b}^ burning carbon and hydro- 

 gen. After giving the comparative amount of heat from various combusti- 

 bles, corresponding with tables we have already published, he proceeded 

 to speak of the advantage of Sieman's furnace, particularly as used in the 

 manufacture of steel. He takes bituminous coal and sets fire to it with a 

 limited supply of air, which drives off a great amount of gas in the form of 

 hydrocarbons and carbonic oxide, which are carried away in a heated state, 

 and afterward brought into contact with air that has been heated by its 

 passage over hot brick work. 



The Chairman said, in burning- anthracite coal (the best known fuel), 

 there was no gain in the round-about prrocess of Siernan, provided there was 

 at first such a supply of air as to form carbonic acid gas. The saving of 

 the waste heat which would escape throug-h the chimney has been effected 

 by a variety of apparatus. Mr. S. may have succeeded in securing a great- 

 er intensity of heat at a given point, but he has not increased the amount 

 produced by ordinary combustion. 



Mr. Hagan desired to present the advantages derived by using the vapor 

 of water, as practiced by him. He did not claim that there was any greater 

 amount of heat produced with than without steam, but he claimed that the 

 intervening of steam between the particles of air made it a rapid conductor 

 as well as generator of heat. He repeated several statements regarding 

 water burning, which have already been reported in the previous examina- 

 tion of this subject. 



Tlie debate was continued by Prof. J03', Dr. Rowelf, Mr. Watson, Mr, 

 Disturnell, and Dr. Richards, but the most interesting views elicited were 

 almost identical with those presented at a previous meeting. 



The subject presented for the next discussion is "The utilization of waste 

 products." Adjourned to June 9. 



1 



American Institute Folyteghnic Association, 

 June 9(hr 1864. 

 Chairman, Prof. S. D. Tillman; Secretary, Mr. B. Garvey. 



Colorado Gold Ores. 



A communication was read from Mr. Henry Garbanati, a member of the 

 Institute, now residing in Central City, Colorado Territory. Accompany- 

 ing the letter were twelve interesting mineral specimens. 



Dr. R. P. Stevens remarked that the particular locality from which these 

 specimens were taken is not stated. They are a portion of the gold bear- 

 ing ores of Colorado. The ores of this territory differ from those of Call- 



