BULLETIN OF THE BUSSEY INSTITUTION. 205 
made long ago by Bobierre,* and often quoted, seemed to fully accord 
with the above view, and to ‘give it direct support. Bobierre’s anal- 
yses indicate as much as 11 or 12, and in one instance even. 27 oy 
cent of “phosphate of lime mixed with alumina and oxide of iron 
It is manifest, however, that statements so little precise as these are 
wholly insufficient to prove that leached ashes are to be regarded as a 
phosphatic manure. Bobierre himself has in fact repeatedly urged 
that leached ashes, such as those examined by him, are very often 
largely adulterated with earth that is rich in alumina and oxide of iron. 
Afi analysis of soapboilers’ leached ashes by Emil Wolff, given in 
his “ Naturgesetzlichen Grundlagen des Ackerbaues,” Leipzig, 1856, 
p. 466, which has served not a little to support the inference that 
phosphoric acid is a prominent constituent of leached ashes, is. really 
not precise enough to lend any strength to that idea. Wolff’s state- 
thent of results reads as follows : — 
Carbonate of lime . . . ine sel (BG 
Phosphate of lime, “Gaage Ste some AAR on oxide ofiron 11.380 
Soluble silica . . . <5 SR ae eae Pe a eat gegen 25 
I oe wk fw we we OD 
PP | P| 
IT ec te ee OO 8 8616 
ITE a Nant ITS Oo val) 4061 
100.16 
It is possible of course that the ashes analyzed by Wolff were ex- 
ceptionally rich in phosphates, or it may be that they contained frag- 
ments of bone, so that there was really as much as 10 or 11% of 
phosphate of lime found in them (‘,e. from 4} to 5% of phosphoric 
acid), but it is much more probable that the iron and alumina above 
reported constituted a very considerable proportion of the 11.3% of 
‘material that is set against their names. It will be noticed that the 
German leached ashes examined by Stein (page 203) contained some 
5% of alumina and oxide of iron. 
- From what has been shown thus far, it seems plain that a little less 
than 2% of phosphoric acid is all that can be allowed in computing 
the average value of dry ashes, whether fresh or leached.| While for 
* Pierre’s ‘Chimie Agricole,” Paris, p. 562 of the first edition. 
t That is to say, with addition of lime, as is the general practice in this 
country, and the custom of soapboilers everywhere. It will be noted that the 
6 or 8 per cent of lime added to the fresh ashes before leaching goes far to sup- 
