1870.] BROOME — ON CANADIAN PHOSPHATES. 251 



discovery by himself, in 18J:7, of the Apatite of Lanark Co., 

 Ontario, and moreover, remarks on the probable value of the 

 deposits, and their application to the manufacture of mineral 

 manures, — a branch of industry then but in its infancy. 



A few remarks upon the geological portion of the subject 

 will be found in a paper read by the author at the Troy 

 meeting of the American Association for the Advancement 

 of Science,* in August last ; as well as in a note, shortly to 

 be laid before the Geological Society of Londonf : but the 

 history of these interesting deposits is by no means complete ; 

 and it is hoped to return to the subject in a future communi- 

 cation to this Society. 



Facts upon the modus operandi of the phosphatic and 

 other mineral manures are more especially desirable ; and it 

 may be well here to briefly to discuss a few points connected 

 with their action upon arable lands. 



With regard to the relation of phosj3horus to plant-life, we 

 have, first of all, the well estabhshed fact that a deficiency 

 of that element in the parent soils produces a corresponding 

 diminution in the weight of the crop, and renders it, more- 

 over, very liable to various diseases ; and that the addition 

 of phosphorus compounds, in a state fit for the nourishment 

 of the plant, always effects a great increase of fertility. But, 

 with regard to this increase, it has been found to be out of all 

 proportion to the actual requirements of the growing plant 

 with respect to phosphoric acid. The waters in contact with 



mentioned Reports, but it ^vill be desirable to quote from that of 

 1847-4S, now, unfortunately, almost inaccessible : — 



" The phosphate of lime is largely contained in wheat, and the ex- 

 haustion of this ingredient is one great cause of the sterility of our worn- 

 out wheat lands. In a grain-growing country like Canada, therefore, 

 the existence of such deposits as these will prove of great importance.'' 



" Under these circumstances, the limestone just described, which con- 

 tains throughout it a large supply of this important substance, is cer 

 tainly well worthy of the attention of our agriculturalists.? 



* On Apatites of Lanark Co., Out., by Gordon Broome, F.G S Proc. 

 Amer. Assoc, 1870. 



Laurentian Apatites of Canada, by the same. Quar. Joui* GeoL 

 Soc. circ. February, 1870. 



