650 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



the milk has reached that exact temperature the warm water Is 

 drawn off and the churning commences. The churning is done 

 by two shafts, with 24 corrugated dashers each, making 10 revo- 

 lutions to one revolution of the crank outside. Cream can be 

 churned as well as sweet milk ; but sweet milk, after being 

 churned, will retain its sweetness from three to five hours. 



Mr. Dibben inquired if this was any different from other plans 

 for violent agitation. 



Mr. Walter said that it was : in this the temperature was 

 kept at 62 deg., which was found to produce the best butter. 



HERMISED INDIA-RUBBER. 



Mr. Seely said, that he had recently visited an india-rubber 

 factory at Beverly, Mass., where he learned some very curious 

 facts in relation to that manufacture. India-rubber had been 

 known about a hundred years, and only within the last twenty 

 years had it been found of much practical use. Very few people 

 knew why it was that india-rubber possessed the property of 

 rubbing out pencil marks, It was generally supposed that it 

 was done simply by friction, but a better explanation was that 

 the rubber, becoming electrified by rubbing, attracted the pow- 

 der of the pencil. As to the discovery of vulcanization, to which 

 was due the present extensive use of that article, and without 

 which it was almost good for nothing, Charles Goodyear had 

 the reputation of it in this country, and Charles Hancock in 

 Europe ; and though Mr. Goodyear was scarcely known in .Eu- 

 rope in connection with the discovery, yet Mr. Hancock admitted 

 that he was led to the discovery of his method of vulcanizing by 

 a piece of india-rubber that he had received from America that 

 had been subjected to such a process. In the town of Beverly, 

 Mass., for some years past, there was a manufacturing company 

 that used a devulcanizing process, taking old rubber, and making 

 it up chiefly into india-rubber cloth, under a patent with which 

 Goodyear's did not interfere. And for the last four years they 

 had been working the raw rubber by a process of vulcanization 

 without the use of heat, as required in Goodyear's patent. The 

 rubber is put into a solution of chloride of sulphur and sulphuret 

 of carbon, .and the change is effected in its properties in a few 

 minutes. This process was called hermising, to distinguish it 

 from vulcanizing. The patent was Mr. Parmalee's. The her- 

 mised rubber possesses substantially the same properties as the 

 vulcanized. It has the advantage, however, of being made of a 



