ON A NEW FORM OF STIRRING APPARATUS 
221 
It will be seen that the exhaustion of the bark has been suflBciently effected 
with 8^ gallons of water in lien of 84 gallons directed to be used in the in¬ 
struction of the British Pharmacopoeia (although a process of percolation is 
attempted in that case) ; and, I may add, that this latter quality, if not actu¬ 
ally adopted at Mr. Squire’s suggestion, does at least coincide with his prac¬ 
tical experience, that cinchona hark cannot he adequately exhausted with less 
than twelve times its weight of water. 
Mr. Bobbins remarked that he had used a similar apparatus with good results. 
ON A NEW FOEM OF STIEEING APPAEATUS TO PEOMOTE 
THE EVAPOEATION OF LIQUIDS. 
BY E. REYNOLDS, F.C.S. 
The author introduced a model of this apparatus, a woodcut of which is 
now given. It was the result of having to find some substitute for manual 
stirring when ext. cinchonas flav. liquidum, B.P., came into use ; the tedious 
operation of evaporating at a temperature of 160° F. requiring to be facili¬ 
tated as much as possible. Having communicated his wishes and ideas to 
Messrs. Garrett, Marshall, and Co., engineers, Leeds, the present apparatus 
was devised. It answered its purpose well, and has since done excellent 
service in the evaporation of liquors in the preparation of extractum carnis. 
The wheel A, when turned by hand, is employed to work the model, but 
in actual service motion is obtained from a shaft driven by the steam-engine. 
This motion drives the wheel B by means of a leather strap, and it is on the 
axle of B that a short crank is fixed, connected, on either side with a hori¬ 
zontal rod that terminates at its other end by joining the upright limb of the 
stirring-arm. The lower end of this limb carries at right angles a strong 
wooden bar, C, and into a wedge-shaped cut made in this the wooden stirrer 
D falls, being kept in position without any fastenings, and capable of being 
lifted out in an instant. It is evident that any number of stirrers, whether 
