188 BULLETIN OF THE BUSSEY INSTITUTION. 
as much again water as acid, = 1575 lbs., a total of 4725 pounds. This 
mixture made 3700 pounds of superphosphate, at a cost for the bone- 
black of $26.25, for the acid of $25, for freight from Boston, $4.50, at 
the outside ; for labor of making, say $5,—a total of $60.75, or say $33 
per ton of 2000 pounds. 
‘¢ Allowing 6 cents a pound for (3.15%) 63 Ibs. insoluble phosphoric 
acid in a ton, the (11.24%) 225 pounds of soluble phosphoric acid cost 13 
cents a pound, or 4 cent more than Mr. White asks for his two qualities 
in New York. So that, although I get a better article than any of the 
eleven superphosphates reported upon by you in No. 1 of the ‘ Bussey 
Bulletin,’ both in respect to quality and cost of soluble phosphoric acid, I 
can in future do better probably with White, even after paying freight, 
because his superphosphates are presumably better made, and so less likely 
to ‘ go back,’ — particularly that of the very high percentage of soluble 
phosphoric acid. Still, my experiment shows that buying acid at retail 
at 22 cents per pound, and making the manure without proper knowledge 
or facilities, in a heap on the ground, I beat the commercial makers 
(except White) in quality, and expose the enormity of their profits. 
“ The freight and labor would both be economized in a properly regu- 
lated wholesale manufacture. My foreman mistook my orders about 
water. Itold him ‘as much water as acid.’ If he had left out the extra 
525 lbs. of water, the result would doubtless have been better. 
‘¢ Superphosphate was made at my farm in 1873 from spent bone-black, 
in the same way as in 1874, except that less water was mixed with the 
acid; and my foreman says it was better than this year’s product, that is 
to say, easier to handle, because less moist and pasty. 
‘« Last year the home-made superphosphate was applied to grass with 
very encouraging results. Upon one part of a 64 acre field that was 
laid down to grass in the spring of 1873, I used my superphosphate in 
connection with nitrate of soda and muriate of potash, of 82% (applied 
at the rate of 340 Ibs., 150 lbs., and 100 Ibs. per acre respectively), while 
another part of the field was dressed with the Manhattan Co.’s ‘ blood 
guano,’ and muriate of potash, applied at the rates of 400 and 115 lbs. 
to the acre. No nitrate of soda was used with the blood guano, because 
that substance was supposed to contain in itself a sufficient amount of - 
nitrogen. 
‘¢ The grass started well upon all parts of the field, but the 24 acres that 
had received the home-made superphosphate were conspicuously better 
than the 4 acres to which the Manhattan Co.’s blood guano was applied, 
until the very severe drought of last year, coming as it did in the grow- 
ing months, withered up all the young grass.* j 
‘¢ Very truly yours, H. SALTONSTALL. 
“Professor F. H. Storer, Bussey Institution.” 
* Mr. Saltonstall informs me that a remarkably heavy crop of grass has 
been obtained this year (1874) from the field in question. Im order to repair 
