108 MR. E. W. BINNEY ON THE PERMIAN AND 



diminislied by rarefaction. But even if no rarefaction 

 took placBj we could breathe in air having much less 

 oxygen than in the worst metal mines we know, if the 

 carbonic acid was removed. This Liebig states, and so far 

 I have proved it, that by removing the carbonic acid by 

 lime from air in which breathing was uncomfortable, the 

 whole seemed quite fresh; candles also burned better. 

 This I have elsewhere described. Nitrogen and some other 

 gases, marsh gas for example, not uniting chemically, and 

 not being altered to a great extent mechanically, but above 

 all not being driven out from any compound in the blood, 

 either by the addition or otherwise of oxygen, do not pro- 

 duce effects so violent as carbonic acid. 



Whatever the explanation be, my conclusion from the 

 experiments is, that the smallest diminution of oxygen in 

 the air breathed affects animal life, if its place is supplied 

 with carbonic acid. 



V. Further Observations on the Permian and Triassic 



Strata of Lancashire. 



By E. W. BiNNEY, F.R.S., F.G.S. 



Read Marcli zist, 1865. 



Introductory Remarks. 



In previous memoirs, published in the Transactions of the 

 Society,* I have given what information I possessed in a 

 fragmentary state, just as I obtained it, of the Permian 

 strata of Lancashire and the north-western counties of 



* Transactions of the Manchester Literary and Philosophical Society, 

 vol. xii. (2nd series), vol. xiii. (2nd series), vol, ii. (3rd series), vol. iii. (3rd 

 series). 



