84 BOTANICAL GAZETTE [FEBRUARY 
and noncalcareous soils, but had no effect on phosphorus. Lip- 
MAN and McLEAN (42) found that composting rock phosphate 
with sulphur increased the solubility of phosphorus. McLEAN 
(48) found an increase of solubility of phosphorus in the sulphur- 
rock phosphate compost when compost was inoculated. The 
presence of soluble phosphates and sulphates did not inhibit the 
action. Lipman, McLean, and Lint (43) found a great increase in 
acidity in the sulphur-floats mixture. Lipman and Jorre (41) 
found no increased availability in phosphorus when acidity was 
increased by the addition of sulphuric acid. Extetr and Harris 
(20) found greater availability of phosphorus in a manure-soil- 
floats-sulphur compost than in a soil-floats-sulphur compost. 
Ames and RicumMonD (2) found no increased availability of 
phosphorus in a compost to which calcium carbonate had been 
added. Acid conditions are necessary for the solution of the 
phosphorus. Brown and Gwrnw (ro) found an increased solu- 
bility of phosphorus in soil treated with sulphur as well as in com- 
posts. Brown and WaRNER (12) found no increased solubility 
of phosphorus in a manure-floats compost, but a great increase 
when flowers of sulphur were added to the compost. 
The use of gypsum as a preservative of the nitrogen in manure 
has been investigated by Hetnricu (30), Vivien (71), Notre (53), 
and by Ames and Ricumonp (1). All these investigators report 
a saving of nitrogen from the use of gypsum on the manure. 
Investigations on the effect of flowers of sulphur on the avail- 
ability of potassium in greensands were conducted by McCati 
and SmirH (45). They found an increase in the availability of 
potassium in composts of sulphur, greensands, and manure, but 
no increase in availability of potassium in composts of sulphur, 
greensands, and soil. 
Reports of investigators who studied the influence of gypsum 
on the availability of potassium do not agree. McCoor and 
Mirrar (46) found calcium sulphate applied to soil lowered the 
freezing point of the soil. No report was given as to the character 
of the compounds that lowered the freezing point. BRapLey (4) 
found an increase in solubility of potassium but not of phosphorus 
in Oregon soils. Briccs and BREZEALE (6) found a decrease in 
