182 
Solubility of Phosphatic Matenals. 
in their turn, dissolve more readily than the phosphates in hard 
rock guano or in coprolites. Indeed all the harder and crystallised 
minerals in the preceding experiments yielded considerably less 
phosphate of lime to water than the more porous and amorphous 
materials. 
Some of the preceding phosphatic substances were next shaken 
with solutions containing separately 1 per cent, of chloride of 
ammonium, 1 per cent, of carbonate of ammonia, 1 per cent, of 
common salt, and 1 per cent, of nitrate of soda ; and the follow- 
ing results obtained : — 
Amount of Phosphate of Lime dissolved by Water containing 1 per cent, 
of Chloride of Ammonium (^Sal Ammoniac^ 
Pure bone-ash, yielding to'j in i Pint. Per GaUon. 
distilled water 1-20 grains! G™ns. Grains, 
of phosphate of lime perj .. '39 .... 3'12 
gallon 
Commercial bone 
ing to distilled 
grains of phosphate of lime j c,^^ 
per gallon " 
Cambridge coprolites yield- j Experiment -20 
. - j after 12 days contact) g.'-g 
\ vnth water \ ' 
•2nd 
ing to distilled water "56 1 
grains of phosphate perUj'g'^^ 
gallon 
•18 
•19 
Suffolk coprolites, yielding] 1st Experiment '15 
■56 grains of phosphate > 2nd „ •IS 
per gallon to distilled water) Mean .. .. •M 
1-60 
1^44 
1-52 
1-20 
1-04 
112 
Amount of Phosphate of Lime dissolved ly Water containing 1 per cent, 
of Carbonate of Ammonia. 
Suffolk coprolites 
1st Experiment 
■21 
1^G8 
2nd „ 
•22 
1^76 
Mean . . 
•215 
1-72 
1st Experiment 
•19 
r52 
2nd „ 
■21 
1-68 
Mean .. .. 
•20 
1-60 
Cambridge coprolites 
In all the preceding experiments the presence of ammoniacal 
salts increased the solubility of the phosphate of lime in the sub- 
stances employed. 
Solutions of nitrate of soda and of common salt of various 
degrees of strength left in contact with finely-ground phosphatic 
minerals for a week or longer, I found, dissolved no more phos- 
phate of lime than distilled Avater did. It is needless to give 
the detailed results, for they were uniformly negative. 
Passing them over, I have now to refer to a number of experi- 
ments instituted for the purpose of determining how far the 
manuring efficacy of half-inch bones, fine bone-dust, and other 
