Analyses of the Ashes of Plants. 
1G5 
we do not feel called upon to legislate; It is just possible that an 
intense heat may reduce and dissijwte phospliorus, alth()ug:h in an 
open shallow dish, with free exposure to air, the result is more 
than questionable, but such a heat would be equally unnecessary 
and inadmissible in the combustions in question. 
We come now to consider whether or not cldorine is lost in the 
burning of plants for analysis. This substance, which usually 
exists in plants as chloride of sodium (common salt) or potassium, 
is in a practical point of view perhaps less important than either 
of the two acids just discussed. It is certainly true that common 
salt is found in large quantities in some plants, more particularly 
those of a succulent watery character, the analyses of turnip-beet, 
&c., given in the Journal, showing a proportion of the salt, 
in some cases equal to nearly or quite one-half of the entire ash. 
But as yet we have no evidence to show that common salt (or 
chlorine in any form) is an indispensable ingredient of plant- 
ashes, for it will be remembered that in the seeds of plants it is 
very frequently altogether wanting, and there is some reason to 
believe that its absence is connected with the perfect ripeness of 
the specimens. 
Whether chlorine is or is not an essential ingredient of ])lants, 
whether it is useful as an acjcnt in vegetable nutrition, or wholly 
unimportant in these respects, we do not here propose to consider. 
Loss of chlorine in the burning of ashes, if it occur at all, may 
arise from two or three causes. It may possibly be given off as 
hydrochloric acid in the early stages of the combustion ; it may, 
as Rose has pointed out, be driven off by the action of the acid 
phosphate in the ash ; or, lastly, it may be lost by the volatilization 
ol chloride of sodium or potassium. 
The following experiments were made with a view of ascer- 
taining how far the alkaline phosphates containing less than 3 
proportions of base are capable of decomposing the chlorides : — 
The ordinary phosphate of soda was taken as the type of 
phosphates containing '2 atoms of fixed base, but as it was con- 
sidered that in all probability the evolution of chlorine would take 
place as hydrochloric acid due to the basic water of the phosphate, 
the phosphate was not further dried than to render it more 
manageable in the subsequent heating. 
Ordinary phosphate of soda was dried on paper till the fused 
salt became tolerably solid ; 23-44 grains of the salt heated by an 
air-flame of gas-lamp lost 8*32 grains of water, or 35-40 per 
cent, (the crystallized phosphate contains G2 • 63 per cent, of water). 
Of this phosphate 69-48 grains were mixed with 29 - 24 grains, 
perfectly dry, of common salt, gently heated at first, and subse- 
quently over the air-flame to redness ; the loss was 23-90: by 
