BULLETIN OF THE BUSSEY INSTITUTION. 35 
magnesia dissolve most readily. Carbonate of lime, on the contrary, as 
he insists, remains undissolved; so that the proportion of it in the ash of 
a leached plant will be larger, through mere subtraction of the other 
inorganic constituents, than in the asa of the original plant. Leaves of 
the hazel-nut, gathered in May and dried at 25° C., gave De Saussure 
6.10% of ashes, which contained in every 100 parts, 26 parts of salts 
soluble in water (mostly carbonate of potash), 23.3 parts of phosphate of 
lime and magnesia, and 22 parts of carbonate of lime; while from similar 
dried leaves that had been simply washed several times with cold water, 
and again dried, he got 5.7% of ashes, that contained, for every 100 parts, 
8.2 parts soluble salts, 19.5 parts phosphates of lime and magnesia, and 
44.1 parts of carbonate of lime. Four per cent of silica was found in the 
ash of the washed leaves, against 2.5% in the ash of the fresh leaves. 
So, too, an ‘‘extract’’ obtained by De Saussure, by boiling oak saw- 
dust in water for half an hour, and evaporating the soluble matter to 
dryness at a moderate heat, gave 6.10% of ashes, of which 51% was 
soluble in water. 
Calvert * noticed that both phosphoric acid and magnesia can readily 
be washed out from cotton fibre, and from various seeds, by means of 
hot water. From a number of samples of pure cotton, he dissolved, 
besides magnesia and some lime, about 0.059% of phosphoric acid; while 
only a trace of that substance could be found in the ashes of the cotton 
that had been leached. From wheat, and from French beans in the pod, 
hot water dissolved a large quantity of phosphoric acid and magnesia; 
and these substances were found also in water in which the kernels of 
walnuts and other nuts had been steeped for forty-eight hours. These 
results are interesting, not merely from their coincidence with the observed 
fact that the ashes of leached woods consist chiefly of carbonate of lime, 
and are poor in phosphates, but from their agreement with the observa- 
tion of De Saussure (‘‘ Recherches,’’ p. 293), that ‘‘ when a plant is 
washed with water, the phosphates of lime and magnesia are removed by 
this liquid in larger proportion than any other of the components of the 
ashes, excepting the alkali-salts.”’ 
It was recognized, very long ago, as a matter of practical experience, 
by potash-makers in Europe, that fire-wood which had been exposed to 
the action of water, as when floated or rafted upon rivers, and that 
straw and leaves which had been exposed to rain, gave ashes that con- 
tained decidedly less potash than the ash obtained from the original 
dry materials.¢ In confirmation of this view, D’Arcett found in 100 
grammes of ashes from new wood, that had been burnt in an ordinary 
chimney, enough soluble alkali to mark 11.6° of an alkalimeter, while 
floated wood, burnt in the same chimney, gave an ash that marked only 
4.35°. 
* “Journal of London Chemical Society,” 1867, 20. 303. 
t Compare Leuchs, “‘ Der Potaschen-fabrikant,” p. 26. 
t “ Annales de Chimie,” 1811, 79. 151, note. 
