In the phosphoric acid column the ' insoluble phosphoric acid is- 

 that part of the total phosphoric acid insoluble in water or a neutral 

 solution of citrate of ammonia. The reverted phosphoric acid is- 

 that portion dissolved by a neutral solution of citrate of ammonia 

 (specific gravity i.og) by treating two grams of the fertilizer, pre- 

 viously washed with water, with loo c. c. of the citrate solution one- 

 half hour at 65° C. It is supposed to represent that part of the 

 phosphoric acid insoluble in water but soluble in soil and root acids — 

 it represents the difference between the total and the sum of the 

 soluble and insoluble phosphoric acids. The available phosphoric 

 acid column represents the sum of the soluble and reverted phos- 

 phoric acid. 



The potash column shows the per cent of potash soluble in water; 

 results published without an asterisk (*) indicate that the potash is- 

 present as chloride or that sufficient chlorine is present in the ferti- 

 lizer to unite with all of the potash. Foot-notes indicate the amount 

 of potash present as sulphate and carbonate. 



The guarantee columns show the percentage of nitrogen, total and 

 available phosphoric acid, and potash guaranteed by the manu- 

 facturer to be present. 



In the table of analyses of fertilizers manufactured for private 

 use will be found the results on three brands of so-called " humus 

 fertilizers" manufactured by the Wallace Fertilizer Co., 147 Nassau 

 St., New York City. 



These materials have not been licensed in Massachusetts but, sO' 

 far as we have been able to ascertain, they have only been sold in 

 very limited quantities and in each case directly to the consumer. 

 The composition of these materials is very similar to the better 

 grades of peat. An analysis of a bona fide sample of dry ground, 

 peat made at this station showed 24.59 P^^ ^^"'^ humus and a total 

 nitrogen content of 2.49 per cent having an availability by the alkaline 

 permanganate method of 35.34 per cent. 



The Wallace fertilizers contain a little more phosphoric acid than 

 is usually found in samples of peat ; aside from this, their composi- 

 tion would indicate them to be dried peat, finely ground. The value 

 of these fertilizers lies largely in their nitrogen and their relatively 

 high percentage of humus, but the price charged for them ($60. oc 

 per ton) is altogether out of proportion to their value. 



