206 SEYLON SOILS AND MANURES. 
holds that volcanoes in their quiescent state, when 
they forth nothing but vapour, ought to be utilized 
as sources of ammonia as much as the liquor of gas _ 
works. ‘‘Of all the products,” he writes, ‘‘that 
contain potash, potassic nitrate is most suitable for 
agricultural purposes.” No.2 of the appendices con- 
tains very valuable ‘‘ Practical instructions on the 
preservation, preparation, and employment of chemical 
manures.” Here also, however, for which we should 
like to quote, we must refer to the book. No. 3 is 
a ‘Collection of the formule: for the chemical manures 
most used, whether alone or in combination with 
farmyard manure.” Every fact and every figure here 
given is suggestive, but we must content ourselves 
with brief quotations. M. Ville thus indicates the 
** Strength of the different ingr edients which enter into 
the manufacture of chemical manures.’ 
Phosphoric acid 
Sources of { percent. Symbol. 
Phosphor- < Calcic superphosphate 15 PO, 
ic Acid. Precipitated calcic Peas 32 
Potash. 
/ Potassic nitrate at 95 perct.. 44 KO 
nee Gal Wenlonde dren Pe 50 
“(do -sulphateat 80 ,, 43 
Nitrogen. 
4mmonic sulphate at 
Sources of 95 per cent.. 20°30 N 
Nitrogen } Sodic nitrate at 95 per cent. 15°72 
( Potassicnitrate at95  =,,, =: 1300 
| Lime. 
Sources of | Calcic sulphate (burnt 
Lime. gypsum) hy uf 39 CaO 
Founded on this table, directions are given for the 
ordering of manures, if, as is preferable, “noricultur ists 
cannot mix for themselves. Appendix No. 3 gives 
‘Practical instructions for the establishment of experi- 
mentalfields and for the interpretation of their results.” 
MR. HUGHES’ HANDBOOK OF CEYLON SOILS 
AND MANURES. 
Mr. Hughes’ remarks on iron in soils summarily 
dispose of an idea propounded by Mr. W. P. Stephenson 
at a recent meeting of the Planters’ Association of 
Mysore that Hemileia vastatrix or ‘‘ red rust” was due 
to an excess of iron in coffee soils, and that, moreover, 
the iron is in a form deleterious to the coffee plant, 
which having taken it into its system nolens volens, 
makes use of the fungus to assist itin ridding itself of 
the noxious element. No doubt iron in certain forms 
