The Canadian Horticulturist. 



197 



The cost of the smaller (l\irnier's) 

 apparatus is very trifling, and the 

 cost of coal has already been stated 

 as I lb, per lb. of evaporated fruit. 

 Mechanical appliances for corinf^ and 

 paring apples are extremely ingenious 

 and very numerous. They are worked 

 by hand and are continuous in action 

 — 7. e., one apple is being "chucked" 

 while a second is being pared and a 



third cored. Peach-paring machines 

 are also in vogue, and cherries, when 

 these are dried, are stoned by a very 

 pretty special machine. None of 

 these mechanical adjuncts to the 

 system of fruit evaporation are ex- 

 pensive, although it must be said they 

 are all specially American pro- 

 ductions. 



PHOSPHORIC ACID. 



THE fourteenth Annual Report 

 of the Ontario Agricultural 

 College contains among other inter- 

 esting matter some particulars about 

 phosphoric acid which we as fruit 

 growers are interested in, from which 

 we select the following portions : 



USES. 



Plants require phosphorus for the 

 development of their seeds, and 

 animals also require it for the struc- 

 ture of their bones. When we speak 

 of phosphoric acid in connection 

 with soils, plants and animals, we 

 refer to a compound of phosphorus 

 and oxygen (P2 O5) : it is the white 

 fume that comes from the burning 

 tip of an ordinary match. It is not 

 found, however, in this condition in 

 soils, plants and animals, but it 

 exists, combined with such substan- 

 ces as lime, iron and alumina, form- 

 ing salts which are termed phos- 

 phates. To say, therefore, that a 

 soil, a fertilizer, a grain of wheat or 

 a bone contains so much of phos- 

 phoric acid means that the acid is 

 present in the combined state of a 

 salt. The most common form is the 

 compound with lime, known as phos- 

 phate of lime, or calcic phosphate. 



Soils require phosphoric acitl for 

 the development of plant life and are 

 often deficient in this regard. Hence 

 the application of phosphates in one 

 of the several forms will often con- 



vert an unproductive soil into one of 

 great productiveness. 



Three samples of soil lately ana- 

 lyzed here gave 0.31 per cent, of 

 phosphoric acid, while one that was 

 said to be unproductive gave little 

 trace of it. Let us take a soil of 

 average quality as possessing 0.20 

 per cent, of phosphoric acid. Twelve 

 inches of surface soil will weigh from 

 one thousand to two thousand five 

 hundred tons per acre, and will con- 

 tain from four thousand to ten thou- 

 sand pounds of phosphoric acid to 

 the acre. There is in the average 

 soil, therefore, a supply of phos- 

 phoric acid (as of other mineral 

 materials) sufficient for many years 

 crop production. That crops cannot 

 thus live upon the constituents of the 

 soil without the regular return to the 

 soil of fertilizers can be explained in 

 two ways : ist, the plant, through its 

 roots, is brought into close proximity 

 to only a small portion of the soil ; 

 2nd, The food is, for the most part, 

 in an insoluble or unavailable form. 

 Hence we need a much larger supplv 

 of plant food in the soil than is 

 required for the immediate necessi- 

 ties of the plant, and some of this 

 food must be in soluble form. 



The difference in value, owing to 

 the state of solubility, will be seen at 

 once from the following trade values 



