PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 445 



eolved. The less time the iron is heated the better. Another 

 method of coating a rod of iron with brass is shrinking it on. 

 The brass tube is heated and the iron rod is cooled, and thus 

 being put together, .as soon as they reassume an equal tempera- 

 ture they will be very firmly fastened together. Electro plating 

 more than fulfils the problem of the alchemists ; for practically 

 it transmutes what we please into gold, giving the articles thus 

 coated all the beauty, finish, and indestructibility of gold, while 

 it adds the strength and lightness of iron if we choose ; and that 

 too at an expense far less than any of the processes by which the 

 alchemists hoped to succeed. 



Mr. Babcock explained the method and advantages of coating 

 common iron with the Franklinite iron which is so hard that it 

 cannot be drilled. In this form it is used for burglar proof 

 safes. 



Mr. Stetson described the process by which a large shaft of 

 cast iron had a new bearing of tin cast about it. The operation 

 had been perfectly successful. 



Subjects for discussion. — Mr. Stetson suggested the question, 

 " Tents and other portable dwellings." 



The subject of " Crucibles," suggested some time since by Mr. 

 Churchill, was selected for discussion at the next meeting. 



Adjourned. 



Association, ? 

 r 21, 1861. 5 



American Institute, Polytechnic 



J^ovimber 



Mr. Tillman in the chair. 



Mr. Johnson requested the Secretary to read an article from 

 an English paper, copied from the Mechanics' Magazine, from 

 which the following is an extract : 



" We believe that the time will come when machinery must be 

 introduced into English horology. There is no reason at all 

 why the hand-labor of English workmen, admirable and unrivalled 

 as it is, should be subject to the disadvantage of contending 

 unaided against the machine-made clocks and watches of America, 

 and we see no reason whatever against the introduction of ma- 

 chinery for the manipulation of the various parts of time keepers." 



AMERICAN GEOLOGY. 



Mr. Nash made some remarks respecting the formation of the 

 mines of Galena, in Southampton ; and Northampton, in Massa- 

 chusetts. 



