CAMPHOR. 339 
undisturbed overnight, to become sufficiently cool, and the next 
day the sublimed camphor was removed and subjected in moulds 
to a pressure of 25001bs. per square inch in an hydraulic press. 
The finished product was obtained in small cakes highly com- 
pressed weighing one ounce. This description, forming part of a 
paper read before the German Technical Society of Philadelphia, 
adds that “ the refining of camphor until within the past few years 
was conducted in quite as primitive a manner as the preparation 
of the crude product,’ and as a description of the European 
method is then given, it is to be presumed that the Philadelphia 
method is the superior oue. 
The European method is as follows :—The crude camphor is 
broken up and mixed with about three per cent. of quick-lime and 
the same quantity of animal charcoal, both in powder. One or 
two per cent. of iron filings is added, and the mixture, after being 
thoroughly blended, is introduced through a funnel into a series 
of globular glass flasks with slightly flattened bottoms and wide 
necks. When the flasks are about half full, the necks are care- 
fully freed from particles that might have attached themselves, and 
they are then sunk in a sand-bath, 50 or 100 together, and heat 
cautiously applied. The heat is suddenly raised from 120° to 
190° C., and kept at that point for half an hour, so as to expel the 
water. The temperature is then raised to 204° C., and maintained 
at that point for 24 hours. When the crude camphor has melted, 
the sand is removed from the upper half of each of the flasks and 
a paper cork placed in the neck. This allows of a lower tempera- 
ture in the exposed part, and the vapour of camphor not being 
permitted to escape condenses on the upper part of the flask as a 
pure cake, leaving all impurities at the bottom. Air, if freely 
admitted, would render the camphor opaque, but that is prevented 
by placing a glass bell-jar over the neck of each flask just as the 
vapour begins to be given off. The whole process lasts about 
48 hours, and when completed the flasks are removed from the 
sand-bath and cold water sprinkled on them. They are thus 
broken, and a large cake of refined camphor 10 or 12 inches in 
diameter and 3 inches thick (weighing 9 to 12 lbs.) is removed 
from each flask. The quick-lme retains the resin or empyreu- 
matic oil; the iron fixes any sulphur that may be present, and the 
charcoal removes colouring-matter. Sand is sometimes mixed 
Z2 
