CHEMISTRY. 189 



and occurs in the West Indian Islands in such enormous quanti- 

 ties, that on one island alone the report of the survey estimates 

 the deposit at no less than 9,000,000 tons. Many other natural 

 phosphatic deposits, found both in this country and elsewhere, 

 are also capable of furnishing an abundant supply of material 

 well suited for carrying out this process at but a very small ex- 

 pense." From a paper read before the British Association at Liver- 

 pool, by David Forbes, F.R.S. 



CHEMICAL CLIMATOLOGY. 



For the last few years Angus Smith has interested himself, in 

 connection with his work as Inspector under the Alkali Act, with 

 inquiries into the condition of the air in various localities in 

 England, not confining himself, however, to places where there 

 exist manufactories, the influence of which would naturally be 

 supposed to be felt. It was once supposed that the differences 

 in the condition of the atmosphere were such as not to be appre- 

 ciated by chemical analysis ; but although there is still much to be 

 desired in the methods and accuracy of the chemical examination, 

 enough progress has been made to enable us to give such an ac- 

 count of the state of the atmosphere in any given place, that it 

 is possible to say, without difficulty, whether it may be considered 

 as tainted by manufactures, or whether it has a large amount of 

 organic matter in it, and, to a small extent, to answer the ques- 

 tion as to the condition of that matter, as it is of importance to 

 distinguish it from that caused by manufacturing processes. The 

 work is still in hand ; it is hoped that materials will be found in 

 it for the beginning of a system of examination of climates, cer- 

 tainly of artificial climates, including places imperfectly venti- 

 lated, as well as those near manufactories. The modes by which 

 air has been studied are (1) By the usual examination for the 

 gases oxygen and nitrogen (Bunsen's method) ; (2) examination 

 lor carbonic acid (Pettenkofer's method) ; (3) examination for 

 ammonia (the Nessler-Wanklyn method) ; (4) albuminoid am- 

 monia (Wanklyn's method) ; (5) nitric acid (Wanklyn's method) ; 

 (6) rapidly and (7) slowly oxidizable matter (by washing the 

 air and using permanganate of potassium) ; (8) chlorides and 

 sulphates ; (9) examination of the rain for the same matters 

 with the exception of the gases. Although our knowledge is 

 still very limited with regard to the conditions of the air tending 

 to produce disease, and although there are so many other consid- 

 erations tending to confuse and bewilder the investigator, yet 

 great importance already attaches to these investigations, and the 

 results thus far obtained are extremely interesting. 



Oxygen. The earliest examinations of chemists were directed 

 to the amount of oxygen and carbonic acid in the air, and the 

 subject of these two gases was admirably worked up by Regnault 

 and De Saussure. "It is abundantly established that the air does 

 differ in the amount of oxygen, but the differences are very small 

 when stated in figures. If we use percentages we throw all the 



