113 



upon the locked-up food ingredients in the soil, setting free potash, and adding to 

 the store of readily assimilable plant nutrients. In the third place, it is especially 

 valuable for its pi'operty of "fixing" ammonia in the presence of moisture. The 

 strong smell of stables, cow-houses and manure heaps is chiefly owing to an escape of 

 ammonia — a volatile compound, the essential constituent of which is nitrogen, 

 one of the three principal elements of plant food. 



Its use, therefore, for sprinkling in stables and cow-stalls is to be strongly recom- 

 mended, for thereby the ammonia is retained, the manure consequently becoming 

 more valuable. 



On rich soils the application of plaster is wont to give an immediate return ; on 

 poor soils better results ai-e obtained by the addition of other and more complete 

 fertilizers. 



As a fertilizer for peas, beans, clover and other leguminous plants it has proved 

 of special value. It has also been advised, owing to its property of liberating potash 

 in the soil, as a manure for Indian coi-n and turnips, 



A sample of gypsum was received from Col. Chus. N. Snow, of Pictou, N.S., of 

 which the following is an analysis : 



Analysis of Gypsum. 



Pel- cent . 



Insoluble rock matter '48 



Lime (CaO) 31-75 



Magnesia (MgO) I'll 



Sulphuric acid (SOg) 45-73 



Oxide of iron and alumina Very slight traces 



Carbonic acid Small quantity 



From the above data I deduce the following percentage composition: — 



Sulphate of lime (gypsum) 97-53 



do magnesia '92 



Carbonate of magnesia "98 



Insoluble rock matter .. "48 



Moisture, etc. (undetermined) "09 



100-00 



As this sample contains but 2-5 per cent, of foreign matter, it must be considered 

 a very pure specimen of commercial gypsum, and one that is well adapted for all 

 the purposes for which this substance is u^ed. 



GAS-LIME. 



The results of my analysis of a sample of gas-lime, forwarded by W. S. Turner, 

 Esq., Cornwall, Ont., are as follows: — 



l^er cent . 



Water 2231 



Volatile and organic matter 12-93 



Insoluble rock matter l-<39 



Oxide of iron and alumina 253 



Calcium sulphate (gypsum or plaster) 209 



Calcium sulphide and sulphite 1*86 



Magnesium carbonate 1"55 



Calcium carbonate (chalk) jS'W 



Lime, slaked 1'44 



lOu-00 

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