The Neglect of Chemistry hy Practical Farmers. 433 



Suppose, for instance, a substance weighing- 456 grains in air 

 to lose 76 grains by immersion in water, the specific gravity of 

 that substance will be 456 -f- 76 = 6. 



It is evident that by weighing any given measure of two sub- 

 stances we do not obtain the actual relative weight of equal volumes 

 of those substances, for their weight greatly depends upon the 

 amount of interstices formed by them ; for instance, a bushel of 

 meal by pressure may be made to equal in weight 2 bushels when 

 lightly filled, although of course the weights of equal quantities are 

 the same ; in other words, their specific gravities always remain 

 constant. 



In concluding my remarks on these tables, I may state that the 

 numbers placed against the analyst's name, refer to the number 

 of individual specimens analysed, and. not to the number of times 

 an analysis may have been repeated, in order to verify its results. 



I will now endeavour, by a few examples, to illustrate the 

 method of using and calculating these tables. 



Exam-pies of Forms 1 and 2. — Given the quantity of ?iny ingre- 

 dient in 100 parts of the ash, to find the quantity of the said 

 ingredient contained in the ash of 100 parts of the entire 

 specimen. 



Suppose, for instance, the ash of wheat grain to contain 47 per 

 cent, of phosphoric acid, as given in Boussingaulf s analysis in 

 Table A 1, and that it was required to know how much was 

 contained in the whole grain, supposing it to be composed of 12.0 

 water, 86.2 org. mat., and 1.8 ash. 



To determine this, all that is necessary is, to multiply the 

 quantity found in 100 parts of the ash by the amount of ash in 

 the specimen, and then divide by 100. Thus we have — 



47.0 (the amount in 100 parts of ash) X 1.8 (the amount of 

 ash in wheat grain) = 84.6, which, divided by 100, gives 

 0 846 as the amount of phosphoric acid contained in 100 

 parts of the whole grain of wheat, in its natural state of 

 dryness. 



By this means. Form 2 was calculated from Form 1. 



Again : Suppose it was desired to ascertain the amount of 

 phosphoric acid in the whole wheat grain, where its proportion 

 of ash was 2.0 per cent., supposing its ash to be similarly consti- 

 tuted to that in the preceding example. Here — 



47.0 X 2.0 = 94.0, which, divided by 100, gives 0.94— the 

 amount required. 



By inverting the calculation, the converse problem may be 



