REPORT OF THE CHEMIST. 163 



SESSIONAL PAPER No. 16 



Our analysis and report is subjoined : — 



Large Small 



Specimen. Specimen. 



Carbonate of lime 53-92 52-08 



Carbonate of magnesia 39 -23 SQ -90 



Oxide of iron and alumini) .... 4 -06 



Insoluble rock matter 3-24 2-06 



For all practical purposes, these samples may be considered identical. They are 

 not true limestone, but that variety known as magnesian or dolomitic limestone. 

 Owing to the presence of the carbonate of magnesia, a ' fat ' lime cannot be obtained 

 on burning this rock — it can only furnish ' poor ' lime, that is, one that slakes badly. 

 This fact, however, should not deter farmers from burning this limestone when their 

 soil is in need of lime. We have no doubt it will yield, when well burnt, a most useful 

 fertilizer for all such soils. 



Island of Anticosti. — A very large deposit of marl, probably 150 acres in extent 

 and of unknown depth, exists at Ellis Bay, Lake Mignon, which is about one-third 

 of a mile in the interior of the island. Having received a request for an examination 

 and report on this material as a fertilizer from M. Comettant, Governor of the island, 

 we submitted a sample to analysis with the following results : — 



Analysis of (air-dried) Marl. 



Per cent. 



Moisture 2-65 



Vegetable and organic mattor 13 -87 



Sand and clay 25 -78 



Oxide of iron and alumina 2-93 



Carbonate of lime 52 -52 



Phosphoric acid Traces. 



Potash -42 



We reported on this marl in the following terms : — 



These data show this material to be marl of fair quality. Judging from it> com- 

 position, as well as from its mechanical condition, it should prove a valuable amend- 

 ment for all sour, peaty and heavy clay soils, as well as for all soils deficient in lime. 



Phosphoric acid is present only in traces, and the percentage of potash is not 

 larger than that in many soils of good average fertility. From these facts it is clear 

 that this sub=;tance cannot be used as a substitute for fertilizers supplying these 

 elements of plant food. 



The proportion of semi-decayed vegetable matter (humus) present slightly 

 enhances the value of the marl, more especially if it is to be applied to light soils, 

 poor in organic matter. 



GYPSUM OR LAND PLASTER. 



Among the naturally-occurring fertilizers of Canada, gypsum or land plaster 

 must be considered as one of the most valuable and important. As, however, it does 



not contain eitlier nitrogen, potash or phosphoric acid, it is not in any sense com- j 



parable to commercial fertilizers, the value of which lies in the percentages of these ! 



constituents they contain. Gypsum is sulphate of lime* and, therefore, as a direct ^ 



supplier of plant food can only furnish sulphur and lime; but as an indirect ferti- j 



*Pure Rypsum 18 composed of lime 32-5 per cent, sulphuric acid 46 o per cent, and water 210 per 

 cent(CaSO^, 2H2O.) 



16— Hi 



