On the Jfflnit ies of differen t Earths for Carbon . 137 



sation taking place on the other side of the large piston which 

 is open to the condenser; and that waste of steam which 

 takes place in engines worked only by the expansive force 

 of steam, from steam passing the piston, is prevented ; for 

 all steam that passes the piston in the smaller cylinder is 

 received into the larger. 



" In such an engine, where it may be more convenient for 

 any particular purpose, the arrangement may be altered, and 

 the top of the smaller made to communicate with the top 

 of the larger, and the bottom of the smaller with the bottom 

 of the larger cylinder; in which case the only difference wi!l 

 be, that when the piston in the smaller cylinder descends, 

 that in the larger will ascend, and while the latter descends 

 the former witl ascend, which for some particular purposes 

 may be more convenient than the arrangement before de- 

 scribed. " 



Mr. Woolf then proceeds to describe various other mo- 

 difications of his invention, and points out means for ap- 

 plying his improvements to the working of steam-engines 

 already constructed and now in use, of which we shall give 

 some account in our future numbers. 



We cannot, however, conclude without observing that 

 the benefits likely to result to the manufacturing interests 

 of this country by Mr. Woolf 's improvement of the steam- 

 engine, cannot possibly be calculated. On this we shall 

 offer a few thoughts on some future opportunity. 



XXIV. Experiments to ascertain whether there exists any 



Affinity letwixt Carbon and Clay, Lime and Silex, se- 



parately or as Compounds united with the Oxide of Iron 



forming Iron Ores and Iron Stones. By David Mushet, 



Esq. of the Colder Iron- Works. 



[Continued from p. 40.] 



JL he following experiments were made with a view to 

 unite carbon with silex by fusion. 



I. Some pieces of very transparent quartz were intro- 

 duced alone into a Sturbridge clay crucible, and exposed to 

 a heat of 16()° of Wedgwood. When cold, and examined, 

 I found the form and number of the crystals entire. The 

 surfaces were slightly vitrified : the colour white pearly. 

 The interior of each crystal was spongy, and adhesive to 

 the tongue. 



L 3 II. Fifty 



