New YorkK AGRICULTURAL EXPERIMENT STATION. 399 
oughly. The size and frequency of the heaps of lime may be 
regulated by remembering that 20-pound heaps placed 20 feet 
apart make about one ton to the acre. After being spread, 
lime should not be allowed to lie upon the surface over night 
or during showers. 
GROUND PHOSPHATE ROCK OR FLOATS. 
Rock-phosphates are known under different names, which 
generally designate the localities from which they come, as, for 
example, South Carolina Rock, Florida Rock, Tennessee Rock, 
etc. When ground to a very fine flour, the rock-phosphate is 
called floats. The phosphoric acid in these materials is largely 
in combination with lime as insoluble phosphate of lime (cal- 
cium phosphate), commercially called ‘bone phosphate of 
lime.” This material when treated with sulphuric acid forms 
a mixture of acid phosphate and sulphate of lime, commercially 
known as dissolved rock, acid phosphate, ete. The phosphoric 
acid in phosphates usually runs from 20 to 25 per ct. but may 
go as high as 35 to 40 per ct. Rock-phosphate in the form of 
floats* possesses little if any value in neutralizing the acidity 
of soils. When used by farmers, it is for the purpose of supply- 
ing to crops the plant-food element phosphorus. Several ex- 
periment stations, notably among them those of Illinois and 
Ohio, have shown some of the conditions under which floats 
can be used to advantage as a source of phosphorus. It can be 
stated, in general, that, when used in connection with liberal 
*The Jllinois experiment station, without making recommendations as 
to reliability or guarantee, states that floats containing 25 to 30 per ct. 
of phosphoric acid, can be obtained from any of the following parties: 
(1) Mt. Pleasant Fertilizer Co., Mt. Pleasant, Tenn.; (2) Robin Jones, 
Nashville, Tenn.; (3) N. Y. & St. L. Mining & Mfg. Co., St. Louis, Mo.: 
(4) Swan Creek Phosphate Co., Chicago, Ill.; (5) Jackson Phosphate Co.; 
Mt. Pleasant, Tenn.; (6) Farmers Ground Rock Phosphate Co., Mt. 
Pleasant, Tenn.; (7) John Ruhm, Jr., Mt. Pleasant, Tenn.; (8) H. D. 
Ruhm & Co., Mt. Pleasant, Tenn.; (9) W. B. Alexander & Co., Mt. 
Pleasant, Tenn. The cost is $2.50 to $5.00 a ton, according to per- 
centage of phosphoric acid, delivered in bulk on board cars at the mines 
in Tennessee. ‘The material would probably cost $8 to $10 a ton in 
New York State. 
