250 EXPERIMENTAL FARMS 



4 GEORGE V., A. 19H 



No. 1S96S. — Lime refuse or waste from + annery, forwarded from Fredericton, 

 \.B. This, as received, was a greyish-white, pasty mass, with a small quantity of 

 hair, but apparently no other foreign matter. The analysis in the air-dried condition 

 gave the following data: — 



Analysis. 



• 



Carbonate of lime 38-79 per cent. 



S'aked lime 54-55 



Mineral matter insoluble in acid 1-05 



Undetermined (organic, etc.) 5-61 



100-00 



An excellent material for dressing lands in need of lime or for composting with 

 ?wamp muck or peat. 



No. 13623. — This was forwarded as a limestone from Cape George, Antigonish, 

 N.S. This rock, it was claimed, had shown itself to have considerable value as a fertil- 

 izer. Our correspondent says, 'We spread it on the land last spring; it melted down 

 like ashes and gave excellent results.' This sample was in hard lumps or fragments, 

 not unlike shale. 



Analysis. 



Moisture 1-93 per cent. 



Mineral matter insoluble in acid 75-44 



Oxide of iron and alumina 10-60 



Lime* 2-94 



Magnesia* 3-41 



Phosphoric acid '17 



* This lime and magnesia exist essentially as carbonates. 



It is obvious /that rock could not be classed as a limestone, since the carbonate 

 of lime does not exceed 5 per cent. The percentage of phosphoric acid is very small, 

 not exceeding that in many soils of medium fertility — and certainly not more avail- 

 able. It is rather difficult, therefore* to understand how this material can have any 

 marked influence as a fertilizer, save in so far as it may favourably affect the mechan- 

 ical condition of the soil. 



GYPSUM OR LAND PLASTER. 



Gypsum or land plaster is a naturally-occurring sulphate of lime, containing 

 about one-fifth of its weight of water, known as water of crystallization. When 

 gypsum is strongly heated (burned), this water is driven off and plaster of Paris 

 remains. This is not used in agriculture, but is much valued in the arts from its 

 property of making a white, hard cement when mixed with the requisite amount of 

 water. 



Gypsum, from the agricultural point of view, supplies lime, an essential con- 

 stituent for plant growth. Since, however, this lime is combined with sulphuric acid 

 and is present in a neutral condition it follows that gypsum cannot take the place 

 of quick or slaked lime, marl or ground limestone (which are essentially alkaline in 

 character) for the treatment of sour or acid soils. Apart from its function in supply- 

 ing lime, it seems probable that the combined sulphuric acid in gypsum has, on 

 certain types of soils, a manurial influence, but it is doubtful if its value from this 

 standpoint is of any great economic importance. 



Undoubtedly its chief value is as an indirect fertilizer, setting free potash from 

 its inert or locked-up stores in the soil. While it does not add to the sum total of 



