SCIENCE OF AGRICULTURE. 119 



besides a little oxyd of iron. The alumina will be 

 scarcely touched. We may estimate all as salts of 

 lime. Evaporate the muriatic solution to dryness, 

 weigh and dissolve in boiling water. The insoluble 

 will be phosphat of lime. Weigh — the loss is the 

 sulphate of lime ; (I make no allowance here for the 

 difference in atomic weights of the acids, as the re- 

 sult is no consequence in this analysis.) 



5. "The earthy residuum, if of a greyish white 

 color, contains no insoluble geine — test it by burn- 

 ing a weighed small quantity on a hot shovel — if 

 the odor of burning peat is given off, the presence of 

 insoluble geine is indicated. If so, calcine the earthy 

 residuum and its filter — the loss of weight will give 

 the insoluble geine: that part which air and mois- 

 ture, time and lime, will convert into soluble vegeta- 

 ble food. Any error here will be due to the loss 

 of water in a hydrate, if one be present, but these 

 exist in too small quantities in 'granite sand,' to af- 

 fect the result. The actual weight of the residuary 

 mass is 'granite sand.' 



" The clay, mica, quartz, &.c. are easily distin- 

 guished. If your soil is calcareous, which may be 

 easily tested by acids; then boil one hundred grains 

 in a pint of water, filter and dry as before, the loss 

 of weight is due to the sulphate of lime, even the 

 sulphate of iron may be so considered; for the ulti- 

 mate result in cultivation is to convert this into sul- 

 phate of lime. 



" Test the soil with muriatic acid, and having thus 

 removed the lime, proceed as before, to determine 

 the geine and insoluble vegetable matter." 



Remarks. 



On the first rule it may be remarked, that this 

 method does not give us all the information needed. 

 We want to know, how much geine, &c. is contain 

 ed, not in the finer parts which will pass through a 



