MECHANICS AND USEFUL ARTS. 107 



Compared with the " marbleized iron/' these objects are better imitations 

 of the stone, because the iron has to be covered with a glass to give it the 

 etone surface, and the thickness of this transparent coating shows itself in 

 certain cases ; and they are more durable, because the different expansibility 

 by heat of the iron and glass, finally causes the latter to crack, and the iron 

 then rapidly rusts. The new material is free from both these objections, 

 but, on the other hand, the imitations of carved work cannot be done so 

 cheaply as in the iron. 



A method recently introduced by Mr. Felix Abate, of Naples, for making 

 plaster of Paris as hard as marble, and rendering it susceptible of receiving a 

 beautiful polish, is as follows : He places the plaster in a drum turning hori- 

 zontally on its axis, and admits steam from a steam boiler; by this means the 

 plaster is made to absorb in a short space of time the desired quantity of 

 moisture, which can be regulated with the greatest precision. With plaster 

 thus prepared, and which always preserves its pulverulent state, he fills 

 suitable moulds, and submits the whole for a short time to the action of an 

 hydraulic press. When taken out of the moulds, the articles are ready for 

 use. 



The plaster thus prepared is perfectly hard and compact, taking the polish 

 of marble. The most delicate bas-reliefs and highly-finished medals may be 

 produced from it with the same perfection as they have in the original. 



THE SALT MANUFACTURE OF'THE UNITED STATES. 



The following comprehensive account of the manufacture and consump- 

 tion of salt in this country was written in answer to a request for the statis- 

 tical information it contains, for the use of a committee of the British Parlia- 

 ment. Its'author is a prominent salt merchant of New York City. 



Estimated Quantity of Salt Manufactured in the United States, per Annum. 



Bushels. 



In the State of Massachusetts (mostly in vats built along the seashore). 46,000 



In the State of New York (Onondaga County), about 6,000,000 



In the State of Pennsylvania (Alleghany and Kiskiminetas river), 900.0UO 



In the State of Virginia (Kanawha and Kings Works) 3.500,000 



In the State of Kentucky (Goose Creek), 250.000 



In the State of Ohio (Muskingum, Hocking River), 500,000 



In the State of Ohio (Pomeroy and West Columbia), 1,000,000 



In the State of Illinois, , 50,000 



In The State of Michigan, 10,000 



In the State of Texas, 20,000 



In the State of Florida, 100,000 



Total, 12,376,000 



There are salt lakes in the United States Territories, one in the south- 

 westerly part of Texas and one or more in Utah, where salt of good quality 

 is found in great abundance. 



Nearly all of the salt manufactured in the United States is made by boil- 

 ing, excepting what is made in Massachusetts, Florida and the Solar Works 

 at Onondaga. 



