206 TlMEHRI. 
tried. By this process coagulation takes place imme- 
diately, and the balata has only to be squeezed to be 
freed of the surrounding water. The balata so pro- 
duced is said, however, to have been unsaleable, and, 
at the best, the report on the sample thus prepared, 
which I sent home for examination, shews that under 
the system, the product: is very much deteriorated. 
Some quicker system of evaporation, however, than 
that at present practised, is evidently very desirable, and 
might, one would think, be easily contrived. This 
opinion led me to enquire of Mr. FRANCIS, the Govern- 
ment Analytical Chemist, as to whether he could not 
suggest a plan that would effect an improvement in the 
time occupied, without requiring an outlay beyond the 
small means of the collectors. To this he has been good 
enough to reply : — 
" I am of opinion that the easiest and quickest way of drying the 
balata milk on a small scale, would be by exposing it in shallow metal 
trays made with double bottom and sides, through which steam could 
be passed from a kettle or boiler. The inner portion of the tray would 
require to be made of sheet lead or zinc — perhaps even copper would 
serve — but iron is quite inadmissible, as it quickly discolours the milk, 
and this objection would likewise extend to tinned and galvanized iron. 
There would be no objection, however, to the outer part of the tray being 
of iron. Of course, the trays could be made of any reasonable size, but 
perhaps it would be preferable to use small ones, made so that any con- 
venient number could be connected together to form a battery through 
which steam from a common source could be passed. A tray 24 inches 
square would hold rather more than two gallons of milk in a layer one 
inch deep, and with proper attention ought to furnish about iolbs of 
dried product in about twelve hours. The principal difficulty in drying 
the milk by spontaneous evaporation as ordinarily practised, is that a 
skin or film of dried gum forms over the surface which retards the escape 
of the moisture beneath. This, I think, would be much less likely to 
happen, especially in the earlier stage of drying, with steam heat ap- 
