26. Before commencing to coagulate, it is essential that the 
■necessary heat and smoke has been raised and that the furnace 
fire is burning briskly. The rate of combustion is then controlled 
by dampers and the requisite heat can be maintained by a slow fire, 
which, with a heated furnace, dries up most of the moisture in the 
fuel while affording sufficient smoke on the belt in its passage over 
the pipes. The smoke chamber is constructed with a raised or lantern 
roof providing sufficient ventilation for the air and smoke surcharged 
with vapour from evaporation of moisture in the latex on the belt, 
thus excluding condensation within the smoke chamber. (It is best 
to admit air at the bottom of the chamber too, and blanket the smoke. 
Free circulation of air allows induced draught and the ready escape 
of smoke from the supply pipes, such dry filtered smoke is then 
retained sufficiently long to take up all the moisture 'evaporated 
during the chamber. When these factors are all in harmony perfect 
coagulation is assured.) 
27. For the process of coagulation the supply vessel, through 
which the travelling belt passes, is made shallow and to contain very 
little latex so as to preclude the possibility of coalescence 
from a smoky belt. This supply vessel is supplied from a reservoir 
at about the same rate that the latex is removed by the belt, and both 
vessels are specified to be placed outside the smoke chamber in view of 
preventing coalescence from the proximity of smoke. 
b 
28. The belts may be made of canvas, or other similar material, 
dipped in rubber solution and vulcanized so as to obtain a smooth 
outside surface, which is necessary for the easy stripping of the belt 
after coagulating. The length of the belts is estimated at forty-two 
feet overall, and the width may vary from a few inches to two feet 
a greater width is considered unwieldy. 
29. As the belt passes through the supply or feeding vessel a thin 
layer of latex adheres to the belt in its most expanded form and is 
then exposed to the action of smoke and this re-agent immediately 
separates much of the water in the latex on the outside of the belt, 
The pulleys, too, which support the weight of the belt — if maintained 
at slight tension, — -afford sufficient pressure on the belt to express out 
most of the remaining water left in the latex on the outside of the belt, 
from where some drops off as clear water, while the the remaining 
moisture is evaporated by heat and smoke and the resulting caout- 
chouc is coagulated into a concentric film of rubber. Smoke is there- 
fore the host in three different functions of the process ; (a) it is the 
host which carries the compound re-agent which separates the water 
from the caoutchouc in the latex; (b) it is the host which absorbs and 
■carries off excess moisture within the chamber ; (c) it is the host which 
fixes the re-agent in the coagulated latex and thus resists oxidization. 
The process, therefore, consists of coagulation by separation of water 
from the caoutchouc in the latex by heat and smoke in concentric 
layers between films of smoke on a travelling belt in which every 
