noug! nai 
: ed to- rot and destruction Peciice Pn i if any, of the oil 
3 were Pgepostd to. work them for oil. The reason was the large percentage of 
use oss - shell, amounting to from 70 to 90 per cent., and even more in the case of 
Recich kernels. Mereover, no economically practicable process of removing the shee 
from the kernel was known. 
a the production of oil from seeds of stone-fruit. That the endeavours to utilize these 
> oils are of particular interest he proves by the following calculation. -According to 
millions of plum trees. From literature on the subject as well as from his own ex- 
a perience the author found that cherries have about 5 per cent., prunes and apricots. 
E- about 10 per cent. of stones. Cherrystones yield about 30 per cent., plum and prune 
stones about 15 per cent. and apricot stones about 25 per cent., peach stones about 
7 per cent. by weight, of oil kernels. Cherry kernels contain about 36 per cent., plum 
_ kernels about 42 per cent., peach and apricot kernels about 47 per cent. of oil. Need- 
_-less to say, these figures only hold good for best selected kernels, the average figures 
being smaller, seeing that a fairly considerable percentage of the stones contain kernels 
of indifferent quality. Nevertheless, given a fair average crop, several million kilos 
of oil could be obtained from stone-fruit in Germany. The stones obtained from fruit 
exploitation and from distilleries could without difficulty be sent to the oil millers; os 
- smaller quantities, collected in individual households, would be gathered by school ea 
_ children as far as possible, and in this manner a large part of the stones of stone- 
_ fruit could be made use of. 
= Alpers has tried to find a process for Separating the shells from ihe kernels in ase 
_ commercially practicable way, so as to eliminate the high cost of carriage of the shells, 
and to be able to press the oil in every kind of oil mill. 
In all probability no machines for cracking the stones of stone-fruit have ever ee 
_ been used in Germany. The author knows of but one factory where it was tried to 
- build machines for cracking plum stones; similar machines for hazlenut cracking as 
‘This state of affairs has induced K. Alpers‘) to Bide the question of racilitating! 
_ the census of 1900 the German Empire possesses 21.5 millions of cherry and 694 
well as some machines for cracking almonds, have been supplied to foreign countries. _ 
3 These machines might be made use of for cracking cherry and plum stones. Alpers 
has tried sorting machines for separating the cracked shells from the kernels after he 
_ had convinced himself that picking the kernels by hand was out of the question. By — 
means of a coffee-sorting-machine it was found possible, in the case of cracked cherry _ 
_ stones, to separate the major part of the round cherry kernels, so that, in view of the 
prices now ruling for oil, the use of these machines might possibly prove of value with 
cherries. However, the author did not continue his experiments with sorting-machines, — 
- as he had meantime found another way for separating the shells from the kernels. 
The specific gravity of plum kernels amounts to 1.05, that of the shell to about 
- 1.18; with cherry, apricot and peach stones the case is similar. It is therefore pos- 
sible, by means of a calcium chloride or chloride. of magnesia solution of a density 
of about 1.15, to separate the kernels of cracked cherry, plum and apricot stones 
- almost completely from their shells. In such a solution the kernels float on the sur- 
face whilst the shells sink. The kernels can be removed with a sieve, after which — 
they are washed, dried and pressed. The process has the advantage of being practicable 
_ on a large scale. 
1) Chem. Zty. 40 (1916), 645. 
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