54° 
THE TROPICAL AGRICULTURIST. [February i, 1889. 
termed one of the essentials of tea manufacture. Im- 
perfectly withered leaf can never be made into good 
tea, and as the production of good tea now-a-days 
makes all the difference between dividends and no 
dividends, the importance of being able to ensure 
perfect withering is obvious. Hitherto, when rain has 
fallen unceasingly for days — we might say weeks — at 
a time, the planter has found himself with the Hob- 
gon's choice of two alternatives before him — either he 
must injure his reputation by making unsatisfactory 
tea, or he must, as has happened frequently, throw 
away large quantities of leaf, which represent a loss 
in out-turn, in the Garden's returns. Under these 
circumstances, the process of evolution in the per- 
fecting of machinery &c, to replace old processes in- 
herited from the Chinese, has open peculiarly slow in 
the important matter of withering as compared with 
the eminently satisfactory advance made in other 
departments of manufacture, rolling, drying, and 
sieving, to wit. "We have much pleasure, therefore, 
in at last being able to proclaim the welcome news 
that good withering in all weathers has now been 
brought within the command of all in an extremely 
simple way. The trouble has been, of course, to re- 
move the excessive moisture in and upon the leaf, 
under saturated conditions of atmosphere, without 
applying artificial heat, to the injury of the leaf. 
With the external air in a saturated condition, and 
added to that, so stagnant as to lack all perceptible 
motion, it has been practically impossible to remove 
the moisture upon and in the leaf, and in the air 
of the withering room, in the proper time. If the 
temperature of the air in the withering room can 
be raised above that of the outside air of course, its 
capacity for holding moisture will be increased, and 
a certain amount of evaporation from the wet leaf 
will take place in the room, which would not occur 
in the saturated air outside. The natural expansion 
of the air inside is not found sufficient however, to 
create a sufficiently rapid change of air by which to carry 
off the excess moisture and the process is too slow for 
satisfactory results, hence a large garden has required 
more space above the engine and " dryers " than can 
be supplied in the usual factory. Consequently, outside 
withering-houses have to be used to supplement the 
space available in the tea-house proper ; and the leaf has 
to be drawn from these and spread a second time, in the 
tea house, as the space in the latter is emptied, thus 
involving much labour and an amount of handling to 
the leaf which is prejudicial to the quality of the 
tea produced. In utilising the waste heat of the en- 
gine and " dryers " on the ground floor by passing 
this heat up into the withering floor, and then in 
rapidly removing the moisture evaporated from the 
leaf by this heat, has been found the solution of all 
the difficulties at once, with a consequent control of 
perfect withering, and a very great reduction of wither- 
ing accommodation, of labour, and of handling. The 
Blaokman Ventilating Company, Limited, has for some 
time past been giving attention to this matter, and 
is now provided with the results of actual experience, 
which will be of so much interest to our readers, as 
making a new departure in tea manufacture, that we 
do not hesitate to quote extracts from a recent letter 
received by the Blackman Ventilating Company, Li- 
mited, from Captain E. T. Skinner, of Silcoorie. 
These are as follows : — " I am delighted to be able to 
inform you that my fans have turned out entirely 
successful. 1 am now entirely independent of the 
weather, for in tho very worst weather, viz. — when 
tho leaf is brought into the factory soaking wet, and 
tho sun is hidden for days, I am able with the greatest 
ease, to wither 100 maunds of leaf in three and a 
half to four hours. In fine weather I can wither 
more than double that amount in the same time. In 
all cases tho wither is equal to the best cold and 
natural wither. You will easily understand this when 
I tell you that the leaf gets withered in a tempera- 
ture of from 86 deg. to 94 deg. The fans are so 
placed that I am able to use both aides of them. 
By utilising the beat generated in the factory by 
the boiler, and tea driers, in very hot weather, the 
temperature of tho tea-house is reduced by 12 deg. 
to 14 deg. In the very worst weather the heat so 
generated is ample for withering purposes. The hot 
air is withdrawn from the tea house and made to circulate 
rapidly over and uo'ler the leaf. A great number of 
planters in the district have seen my arrangement 
of your fans, and all pronounced it a thorough suc- 
cess. I never now wither in the sun and never use 
half the withering accommodation I formerly required." 
Coming from so capable an authority such testi- 
mony aB the above speaks sufficiently of itself as to 
the unqualified success of this system. 
It only remains to point out a few details con- 
nected with the method of working the system. The 
withering floor is filled with withering trays, as is 
already usual in many districts. It is opened almost 
right across the building, at the end on the left of 
the drawing, to allow the heated air to be drawn 
up to the withering floor, and so as to distribute 
the supply over almost the whole width of the floor. 
The tray shelves should run across the building, with 
gangways down each side, as by this means there 
will be no Royal road for the air to travel too 
directly to the fan placed in the middle of the floor, 
at a distance from the hot-air entry. The air will 
thus be obliged to find its way through the series 
of trays, as the flooring of the gangway is carried 
to the end of the building (thus closing only that 
part of the floor at the end up which the hot air 
travels), the current of air can be checked from too 
free a passage down the gangways. The Blackman 
fan "thrusts" as well as "sucks" air, so it draws the 
air through about two-thirds of the trays and forces 
it through the remaining third. The draught thus 
occasioned not only assists evaportion, but removes 
the evaporated moisture from the house. In very 
wide houses, it may be desirable to have two or three 
smaller fans abreast of each other in place oi one 
large fan in the centre in order to ensure an even 
distribution of the current. The great assistance to 
be obtained from these fans will be evident by taking, 
for example, the case of the 48 in. fan. This fan will 
require 2 horse power to drive it at its maximum. It 
can, however, move 30,000 cubic feet of air in one 
minute. This means that if there were no trays to 
resist the passage of the air, this fan could move the 
air contained in a room 125 ft. long by 30 ft. wide by 
8 ft. high in one minute ! The fan can be driven by 
a rope or belt passed up through the floor below the 
fan, from a driving drum on the ordinary shaft. 
Owing to the resistance offered by the trays, two 
such fans would probably be found necessary in a 
house of the above dimensions. The fans of this size 
weigh 3 cwt 1 qr. 24 lb. each, or, packed for shipment, 
5 cwt. 3 qr. 20 ft, and in cases measure 5 ft. 5 in. square 
by 1 ft. 5 in. By the addition of a simple form of 
stove, these fans can also be applied to outside with- 
ering houses, if power to drive then can be obtained. 
In order to prevent improper draughts entering the 
tea-house, all windows, &c, can be stopped in a very 
simple way hy oiled thin canvas stretched and tacked 
on to frames to fit in the windows. These will be 
found to admit as much light as some forms of 
glazing, and are much cheaper. Owing to the heat 
being removed by the fan, these windows will be no 
longer required for ventilation. — Indian Tea Gazette. 
♦ 
SWEET CASSAVA; 
(Jatropha manihot or A'ipi.) 
By H. W. "Wiley. 
About the middle of March, this year, I received 
from Mr. R. H. Burr of Bartow, Fla., a package 
of cassava roots. These roots reached the department 
in fine condition, being apparently as fresh as the 
day they were taken from the soil. After careful 
sampling and cleaning, a sufficient quantity of the 
roots wns cut into thin slices and thoroughly dried. 
In a definite weighed portion, sampled as carefully as 
possible, the precentage of moisture was determined. 
The dried aud powdered roots were preserved for 
future analysis. Owing to a press of other matter, 
