442 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



Mr. Garbanati remarked that the berths in this tent were to be 

 easily removed, and would serve as litters to bring our wounded 

 oflf from the battle field. 



This tent was referred to the Section of Mechanics. 



PHOTOGRAPHIC APPARATUS. 



Mr. M. Ormsbee, of Boston, exhibited an apparatus for taking 

 photographs, daguerreotypes, and ambrotypes, of any desired 

 size or number with facility. A machine had been constructed 

 upon the same principle, of larger size, wdiich would take 616 

 upon one plate, so that it would be possible upon a sunny day to 

 make 250,000 pictures. 



The apparatus was referred to the Section on Chemistry. 



IMPROVED GUN BOATS. 



Mr. Fisher proposed that each member should be invited to 

 bring a drawing of an iaiproved gun boat a fortnight hence, the 

 whole to be open to criticism and amendment. He advanced the 

 theory that no invention is ever perfected by a single individual ; 

 and hence the desirability of co-operation. 



AMERICAN GEOLOGY, 



Dr. Stevens, in continuation of his lectures on this subject, 

 exhibited and explained a map of the American Continent in the 

 earliest geologic epoch, when in his opinion it first assumed shape, 

 so far as it can be ascertained after the vast dilapidations and 

 wearing which it has since undergone. In the Paleozoic sea, now 

 called the Atlantic ocean, but then covering a large part of the 

 U. States, were deposited the limestones, shales and sandstones of 

 a subsequent era, to a thickness of from 650 to 10,000 feet. Up 

 to that time there were no land plants. In those seas we first 

 find the remains of ancient life. The seas w^ere suddenly filled 

 with various forms of life ; rude to appearance in their forms, and 

 yet according to their species as perfect as any forms of the pre- 

 sent day. Th» minerals deposited in this age were quite distinct 

 from those deposited prevtoTtsly. They consist mainly of copper, 

 only found in this age of the world and characteristic of it, of 

 lead, of gold in various places, and of certain kinds of iron, among 

 which are the famous Tennessee tough iron, and what is called 

 the lenticular iron ore. 



The animal kingdom is arranged by Cuvier in four orders : 

 Vertebratse, the Articulata?, the Molluscse, and the Radiatse. If 



