MINERAL SUBSTANCES IN ORGANS OF PLANTS. 267 
If we compare the composition of these three ashes, we 
arrive at the following conclusions: — 
1. The amount of salts soluble in water augments nearly 
exactly eight times, from trunk to fruit. The soluble salts 
of the ashes of the trunk, leaves and fruit of the plant ex- 
amined, are in the proportion of I : 2 : 8. Here manifestly 
one intermediate proportion is left out. Is it, perhaps, formed 
by the flowers ? 
2. The phosphoric salts augment from trunk, and this is 
taking Jplace at the expense of the carbonic combinations 
which from trunk to fruit are diminishing from 86 to 45 per 
cent. 
To show the increasing amount of phosphoric acid in the 
ashes from trunk to fruit in one more instance, I examined 
three ashes of sambucus nigra solely with reference to their 
phosphoric acid. The phosphoric acid was determined after 
a method communicated to me by Prof. Liebig ; a method 
which for its exactness and facility of execution is preferable 
to any other. The ashes to be investigated for phosphoric 
acid are merely to be dissolved in nitric acid, and the solu- 
tion precipitated by an excess of acetate of lead. The pre- 
cipitate contains phosphate of lead and sulphate of lead, if 
sulphuric acid was present, and basic nitrate of lead. It is 
to be calcined and weighed. It now consists of sulphate of 
lead, phosphate of lead, and oxide of lead. It is then again 
to be dissolved in nitric acid, afterwards sulphuric acid added, 
and next some alcohol, and the obtained sulphate of lead is 
to be weighed. From this the quantity of lead is calculated, 
which, as well as the sulphuric acid, the amount of that 
latter acid having been determined on treating another 
portion of the ashes by baryta, are deducted from the 
weight of the sulphate and phosphate of lead and oxide of 
lead. The remainder is phosphoric acid. 
The quantity of phosphoric acid found by this method in 
the ashes of the trunk amounted to 10.5 per cent.; in those 
of the leaves to 13.6 per cent*; in those of the fruit to 20.3 
per cent. 
