114 The Fermentation of Cacao’ 
time required for completing the process was 
stated to be two days.’ 
Consul Spengler, now in Lisbon, but 
formerly manager of the Monte coffee planta- 
tion in San Thomé, introduced a modern type 
of tunnel-drying some years ago. Indepen- 
dently, and without knowing of this method, 
I also worked out a scheme of tunnel-drying, 
which differs from that of Spengler in that 
a ventilator is attached to one end of the 
tunnel, and the construction is as follows: Two 
tunnels, divided by a middle wall, are 20 m. 
(65 ft. 6 in.) long, 1°5 m, (4 ft. 11 in.) wide, 
and 1°75 m. (5 ft. 9 in.) high. A 20-cm. or 
8-in. gauge rail runs down the centre of each 
tunnel, the latter being closed at the ends by 
double doors. In a convenient position at one 
_end of the tunnels is a heating apparatus from 
which the hot air is driven through the venti- 
lators into the separate tunnels. In order to 
increase the draught, a flue communicates with 
the other end of each tunnel, just as in Spengler’s 
method, and this draws off the hot air. Trays 
filled with cacao are placed on small trolleys 
and these are run into the tunnels, and as soon 
as the cacao on the front trolleys are suff- 
ciently dried, these are run out at the other 
end, where the hot air enters, and the trolleys 
on which the cacao is not yet sufficiently dry 
' This is on the principle of the American fruit dryers, 
and cannot prove a success unless a fan, or other means 
for providing a forced draught, is supplied.—H. H. S. 
