ANALYSIS OF A PULMONARY CALCULUS. 207 



It would appear thence that there are at leaft two kinds of Probability that 

 pulmonary concretions: thofe which Morgani obferved tobe*"^^^ 

 thrown up by coughing, anfwer the defcription of the the carbonate 

 calculi, examined by M. Fourcroy, and thofe it has been ^J^ ?hofphate 

 ftated were compofed of phofphat of lime, while the con- 

 cretions which Were hard and heavy like marble, it is pro- 

 bable agree in their chemical compofition, as well as in their 

 external characters with the calculus, which is the fubject of 

 this paper ; this it has been proved was compofed of carbonate 

 of lime. A queftion then naturally arifes, as to the forma- 

 tion of carbonate of lime in the lungs. Was it depofited as 

 fuch from the blood or formed in the Bronchia? by the chemical 

 combination of its principles ? We have certainly not hitherto 

 been able to detect carbonate of lime in the blood, and we 

 have no reafon to fuppofe that the phofphat or lime which 

 exifls in it, can be decompofed by the carbonic acid which 

 is formed in the lungs, to avoid thefe alternatives, the chemical 

 phyfiologift might be inclined to look to an external caufe for 

 the formation of this extraordinary fubftance, and with this 

 view, he would enquire into the previous occupation of the 

 perfon from whofe lungs it had. been taken ; but he would be 

 checked in his enquiries by the recollection that the fame 

 chemical affinities which can form carbonate of lime in the 

 teeth and bones, may by an accdental coincidence depofit 

 it in the lungs. 



XII. 



Of the State of Vapour fubfijllng in the Atinofphere. ^j/Richard 

 Kirwan, Esq. LLD. F.R. S. and P. R. LA *. 



V APOUR or moifture in the atmofphere may fublift in denfe The fubfiftence 

 air, or in air highly rarified : that it is found in the former is J^2«S in* 

 well known, and that it may fublift in the latter appears by the highly rarefied 

 obfervations of Bouguer, for he faw clouds three or fourhun- air * 

 dred toifes above Chimboracho, and confequently at the 

 height of twenty-two thoufand five hundred and twenty-eight 

 Englifh feet, or 4,3 miles over the level of the fea ; a height 



* From his eflfay on the variations of the atmofphere j In the 

 Irilh tranfa&ions, Vol. vin\ 



at 



