122 ANNUAL OF SCIENTIFIC DISCOVERY. 



turnings or granulated metal with which they are filled. The steam thus 

 overheated is conducted into a reservoir of cast iron, furnished with a ther- 

 mometer and manometer indicating its heat and tension ; then it passes to 

 the carbonizing apparatus. To pass out of this apparatus, the steam and gas 

 are conducted in. the enveloping tubes mentioned above ; the condensed 

 water and the gas, now nearly cold, pass out, to be rejected by an arrange- 

 ment for this purpose at the lower part of the apparatus. The air for pro- 

 moting the combustion is heated by passing along a portion of the walls 

 of the chimney and the vent holes before arriving under the grating, by 

 which means heat is economized. The following are the advantages of the 

 method : 



1. Only one fire is used for producing the overheated steam ; and a sin- 

 gle fireman suffices. 



2. Only the amount of water actually necessary for producing the steam 

 is heated, and just as it is required. 



3. The greater part of the heat is utilized, which was before carried off 

 by the steam and gas and totally lost. 



4. The use of metallic furnaces renders it easy to multiply the heating 

 surfaces, and at little cost. 



5. The heating is regular, the temperature very equal, and the products 

 obtained are uniform. 



6. The best heating effects are obtained by the arrangement for bringing 

 the hot air under the grating. 



The Committee hence recommend an appropriation to enable the powder 

 establishment of Esquerdes to make these arrangements. The appropria- 

 tions have accordingly been authorized." 



GIGANTIC CLAY MODELS. 



Among the novelties of the new English Crystal Palace, are clay models 

 of various forms of extinct animals, constructed of the natural size, and 

 perfect in all their anatomical details and in the characteristic features 

 peculiar to the living animals. Some of these models contain thirty tons 

 of clay, which have to be supported on four legs, as their natural history 

 characteristics would not allow of recourse being had to any of the 

 expedients for support allowed to sculptors in ordinary cases. In the 

 instance of the Iguanoclon, this was no less than building a house upon four 

 columns, as the quantities of material of which the standing Iguanoclon is 

 composed consist of four iron columns nine feet long by seven inches in 

 diameter, 600 bricks, 650 five-inch half-round drain tiles, 900 plain tiles, 

 38 casks of cement, and 90 casks of broken stone, making a total of 6-10 

 bushels of artificial stone. This, with 100 feet of iron hooping, and 

 20 feet of cube inch bar, constituted the bones, sinews, and muscles of 

 this large model, the largest of which there was any record of a casting 

 having been made. 



