160 NATIVE IRON, &tf. 



Native irons. Refpe&ing the kinds of iron called native, they all contain 



nickel. The mafs in South America is hollow, has concavi- 

 ties, and appears to have been in a foft or welding itate, be- 

 Caufeit has received various impreflions. 



The Siberian iron has globular concavities, in part filled 

 with a tranfparent fubftance, which, the proportional quantity 

 of oxide of iron excepted, has nearly the competition of the 

 globules in the llone from Benares. 



The iron from Bohemia adheres to earthy matter iludded 

 with globular bodies. 



The Senegal iron had been completely mutilated before it 

 came under my examination. 



From thefe facts, I fliall draw no conclufion, but fubmit 

 the following queries. 

 Have thefe all 1ft. Have not all fallen ftones, and what are called native 



the fame origin ? y the fame QT > > ? 



and from me- ° 



teors ? 2dly. Are all, or any, the produce or the bodies of meteors ? 



And, laftly, Might not the ftone from Yorkfliire have formed 

 a meteor in regions too elevated to be difcovered ? 



Specimens of the Benares and Yorkfliire ftones have been 

 depoiited, by the Prefident, in the Britifh Mufeum. 



Expedients and Obfervations on the Heat and Cold produced by 

 the Mechanical Condensation and Rarefaction of Air *. By 

 John Dalton. 



Well knojvn IF a thermometer be inclofed in a receiver and the air fud- 

 fa&s that tie denly condenfed, the thermometer rifes a few degrees above 

 rifes in con- * ne temperature of the atmofphere j and if the air be exhaufted 

 denfed and falls from a receiver inclofing a thermometer, the mercury finks a 

 xn rareae air. £ ew degrees immediately ; but in both cafes after fome time it 

 refumes its former ftation. Thefe fads are well known to 

 philofophers of the prefent age, but they do not all agree iii 

 the explanation of them. Thinking the fubje<5t worthy of elu- 

 cidation, I was induced to inftitute a feries of experiments for 

 the purpofe, which I apprehend have led to a clear demon- 

 Juration of the caufe of the phenomena, and moreover makes 



* Manchefter Memoirs, V, 515. 

 2 the 



