ON THE ORIGIN OF SEVERAL MECHANICAL INVENTIONS. 161 



tracting the carbonic acid from the atmosphere is not so 

 great as the old experiments of Vogel and others would 

 lead us to suppose. 



2. That the sea in our latitudes does not act in increasing 

 the amount of carbonic acid in the air above the ocean, as 

 found by Lewy over the Atlantic near the equator. 



3. That the differences observed in the air of night and 

 day by Lewy on the Atlantic, are not perceptible in the 

 air above the Irish Sea. 



4. That in the month of August 1865, the mean quantity 

 of carbonic acid in the atmosphere of the Irish Sea wal 

 3"o8 in 10,000 volumes of air. 



In conclusion, I beg to acknowledge the kind attention 

 which I received from Captain Temple, and from his crew, 

 during my stay on board his ship. 



IX. Notes on the Origin of several Mechanical Inventions, 

 and their subsequent application to different purposes. — 

 Part II. By J. C. Dyer, Esq., V.P. 



Head December 12th, 1865. 



On the Employment of Steel for Multiplying Engravings. 



At the beginning of the present century (upon the death 

 of Washington, and in commemoration of that event) Mr. 

 Jacob Perkins (then a silversmith at Newbury Port, near 

 Boston) undertook to make and supply copies of a " Wash- 

 ington Medal ;" and as they were likely to command a 

 large sale if speedily brought out, it occurred to him that 

 this might be effected in a summary way, by the process 

 of transferring the engraved design from prepared steel 

 dies. 



SER. III. VOL. III. M 



