Polytechnic Association Proceedings. 621 



patented the process, and constructed a machine for making ice on 

 a lar2:e scale. It is like a tubular boiler contaiuino: the chimocrene, 

 the water being frozen in the pipes, which are so constructed that 

 the ice may be readily removed. It was stated that ice may be 

 thus made at a cheaper rate than by the ammonia process. 



CLOSE OF THE SESSION. 



At the conclusion of the discussion on the formation of ice, 

 Prof. Tillman retired, and, on motion, Dr. Warren Eowell took 

 the chair. 



S. H. Maynard, Esq., in a few appropriate sentences, compli- 

 mented the permanent Chairman for his exertions to further the 

 interests of the Polytechnic, and concluded by moving that the 

 thanks of the Association be tendered to Prof. S. D. Tillman, for 

 the able and dignified manner in which he had presided at their 

 discussions. 



Dr. John B. Rich seconded the motion, and spoke of the large 

 amount of interesting matter which had been gathered by the 

 Chairman, chiefly from foreign journals. 



Dr. D. D. Parmelee followed, approbating the zeal and ability 

 evinced by the Chair. 



The resolution was adopted with applause; after which, the 

 Association adjourned to September. 



September 19, 1867. 



Prof. S. D. TiLLMAK in the chair; J. Wtatt Rbid, Esq., Secretary. 



The first autumnal meeting was called to order by the Chairman, 

 who, after a few congratulatory remarks on the presence of so 

 many of the regular attendants of the Polytechnic, offered the fol- 

 lowing summary of scientific news, which had been made up by 

 him weekly during the vacation commencing on the second Thurs 

 day in June. 



PURE ACETIC ACID. 



Picter, of Berlin, uses baryta (baramat) in preference to soda 

 (sodemat) or lime [calcamat) in the manufacture of pure acetic acid 

 from crude wood vinegar. The acetate of baryta withstands the 

 roasting necessary to get rid of the empyreumatic matters better 

 ilmn the acetates of lime or soda, in consequence of which there is 

 less loss of acetic acid. 



