ANNUAL ADDRESS, MDCCCLXXIII. 45 



as it is expelled from our lungs, through lime water. 

 The lime unites with the carbonic acid and separates in 

 a milky precipitate from the water ; but if a continued 

 supply of this gas is kept up the carbonic acid becomes 

 a solvent and all the lime goes into solution again, not as 

 a bicarbonate, as might be and is supposed, but simply as 

 carbonate of lime (CaOCCte) dissolved mechanically by 

 an excess of carbonic acid. Is it not possible for there 

 to be conditions in the sea, as yet unnkown to us, under 

 which the excess of carbonic acid may be withdrawn? 

 Then the limestone would be deposited. This process I 

 suggest may be the corollary to the organic one, and both 

 animal and chemical agency may be simultaneous or alter- 

 nating. We should then get the result we now see, 

 namely, limestones composed of partly mineral and partly 

 structural matter, and should get the same mineral result 

 as we see in stalactitic and crystalline accretions, and 

 partly in the same way with the addition of fossil forms. 

 But the weighty and authoritative argument of Professor 

 Bischoff goes entirely the other way. He says it is im- 

 possible for carbonate of lime to be precipitated in the 

 sea, because there is a slight excess of carbonic acid 

 always there, which is more than able to dissolve all the 

 lime that is being poured into it by rivers and tidal 

 action washing against limestone coasts. He also says 

 that the lime thus coming into the sea is in quanity just 

 what is extracted from it by shell fish, &c., and so a 

 kind of balance is kept up. He states that sufficient 

 lime is annually carried into the sea by the river Rhine 

 to give shells to 332,539 millions of oysters. He found 

 a little more than l per cent, of carbonate of lime in 

 the sea water between England and Belgium, and 1J per 

 cent, of carbonate of magnesia. He gives the quantity 

 of carjbonic acid present in sea water to be five times 



