132 



The Canadian Horticultufist. 



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Phosphate Meal. 



Oar J^xclHiPUcs. 



A NEW source of phosphoric acid is 

 phosphate slag. Tiiis consists of the 

 slag remaining from the manufacture 

 of steel or pig-iron by the Thomas pro- 

 cess. The dephosphorization of the 

 iron takes place by melting the iron 

 with 'lime in a current of air, whereby 

 the pig-iron, rich in phosphorus, is con- 

 verted into steel, free from phosphorus. 

 The phosphorus of the pig-iron is thus 

 converted into phosphoric acid, which 

 unites with lime and forms phosphate 

 of lime. The melting mixture of phos- 

 phate of lime with the excess of lime 

 and combinations of the iron and man- 

 ganese, is called Thomas slag. It is 

 finely ground, and it is well spoken of 

 in Europe as a cheap source of phos- 

 phoric acid for crops that do not need 

 this element in an immediately avail- 

 able form. Analyses of German phos- 

 phate slag and of English slag, made 

 at the Massachusetts experiment station, 

 are as follows : 



German Slag. English Slag. 



Water 5.08 0.37 



Iron and alumina I5-9S 8.55 



Total phosphoric acid 21.05 1S.91 



Lime , 53-97 49-22' 



It is claimed that phosphoric acid 

 can be furnished at less cost in 

 this phosphate meal than in any of our 

 known mineral resources of insoluble 

 phosphoric acid. A few sales of it 

 have been made in the Connecticut 

 valley at $15 per ton. If we reckon 

 the phosphoric acid at two cents per 

 pound, the price put upon insoluble 

 phosphoric acid in rock, the slag analy- 

 zed has a valuation of $8.42 and $7.56 

 per ton respectively. We are glad to 

 see that the Massachusetts station pro- 

 poses to make some experiments to 

 test the availability of this phosphate 

 and see whether its acid is worth more 

 than two cents per pound. Director 

 Goessmann says of it: " The compo- 

 sition of the slag is peculiar on account 

 of an excess of caustic lime, which 



favors a breaking up into minute parti- 

 cles when exposed to air and moisture 

 The more finely ground, when exposed 

 to atmospheric influences, the more 

 rapidly a general disintegration ensues. 

 This behaviour tends to diffuse the 

 phosphoric acid and favors absorption 

 by the roots. No previous treatment 

 by acids has been found necessary to 

 secure satisfactory returns when used 

 as a phosphoric acid source for plant 

 growth. On account of the alkaline 

 reaction of the 'phosphate meal' no 

 ammonia salts or organic nitrogen 

 compounds should be used as an 

 admixture for the production of more 

 complete fertilizers. In case nitrogen 

 is to be applied, nitrate of soda is used 

 to furnish the element. Muriate of 

 potash and kainit are recommended as 

 a source of potash." Ex. 



Oup Native Plums. 



If, as we are told by Dr. Gray, the 

 European Plum, Primus doniestica has 

 its original in the almost inedible sloe, 

 and yet there have been derived from 

 it such a multitude of delicious varie- 

 ties as we now cultivate, what may not 

 be hoped, as the result of high culture, 

 crossing and selection, from native spe- 

 cies like those of the American contin- 

 ent, which, when merely growing wild 

 in thickets along the water-courses, send 

 such waves of rich perfume across the 

 land leeward ? It seems to me that in 

 these native Plums we have the easy 

 potentiality of a class of fruits that will 

 give to the " cold north " a two months' 

 supply of fresh fruit which will, in time 

 abolish all regret that the Peach, Nec- 

 tarine and Apricot are denied to them 

 by a vigorous winter. For it is a fact 

 that our Prunus Americana has a range 

 far north of our national boundary 

 being, in fact, the hardiest of all tree 

 fruits. It is ot the most easy cultivation, 

 and very susceptible of improvement. 



