i88 
THE IROPIOAl. AQRIOULTURIST. 
1, 1891. 
THU Al'I’KUACIIINO KEVOJXTION' IN 
TEA EIJUXU. 
A TEMi’EnATUuE Beoommendeu tow hi liv Nearly 
100° luAN THAT Generally Employkl ! 
Wo have hnd a visit irom Mr. Davidson o£ 
“ Siroooo " fame, — the patentee and manufacturer 
of many hundreds of updraught and downdraught tea 
driers, which are so largely in use in India and 
Ceylon. Mr. Davidson has been connected with 
tea, as planter, buyer and eellsr, and, latterly, 
in the useful and important capacity of machinist 
since 1864, He knows as much about the culture 
and manufacture of tea as any man living, per- 
haps ; but like all truly scientiflo men be has not 
only not been ashamed of ever learning, but has 
bad the courage fairly and fully to face and 
unlearn wliat seemed fixed principles in the 
pursuit. Until recently Mr. Davidson firmly 
believed in and taught the doctrine that a 
temperature of 240 degrees was the best in tea 
drying. A series of most interesting experiments 
in the laboratory and with bis downdraught driers 
has convinced him that he has been mistaksn ; and 
while on estates in India he has doubled the average 
value of teas by preparing them on the new 
principle of drying at so low a temperature as 
130°, This, ho explains, means a temperature of 
160° in the heat of the siroooo, the evaporation 
of moisture from the leaf keeping it down to 130°. 
Before getting so dry as to rise above that tern, 
peralure, Mr. Davidson advises that the tea 
shouLd, near the olose of the drying process, 
bo removed to and llnisbcd eff in a separate 
sirocco, the heat of which should be only i:i'j°. 
To our question whether this would not greatly 
extend the tirr.e required to dry quantities of tea, he 
replied that tuoh an objection was obviated by power 
applied to tho downdraught which would cause the 
air to pass through the tea at the rate of eighty 
miles an hour. The philosophy of tho reformed 
process Mr. Davidson explains 10 be tho preserva- 
tion by tho use of tho reduced temperature of tho 
volatile oil, on wbiob, more than any other con- 
stituent, the fine flavour of tea depends. At tho 
high temporalnres of 240 deg. and oven more 
formerly used, this oil was dissipated, and what 
Mr. Davidson deems the very poor substitute 
which is teobnitally called “ maltiness ” took Us 
place. We quite uuderstood Mr. Davidson to add 
that tho carrying on of Ibo ouring process at a low 
temperature would also put an end to the 
persistently repeated complaints of the non-keep- 
ing qualities of Ceylon tea. Ho ascertained in 
the ocurEo of hia investigations that tho better 
keeping qualities of the weaker China teas is 
due to tho roally low temperature at wbieh they 
are fired.— All this is not only exceedingly in- 
teresting but very important, and it is a 
fortunate ooinoidcnce that Mr, Dividson should 
land at Colombo during the festivities which will 
draw BO many leading planters to Colombo. To 
these Mr. Davidson can fully explain and with 
them be own discuss the principles on which the 
new process, which really amounts to a revolution 
in tea drying, aro founded, with the varions de- 
tails of power, exhaust fans, A’o. After a short 
time in Colombo (when appoinmenta to meet him 
can be made through Messrs. Maokwood & Co,) Mr. 
Davidson, to whom Ceylon is new (he having only 
touched at Galle a score of years ago), means to take 
a tour through the tea estates, the results of 
which may bo profitable to him in giving him 
additional information and leading to new oon- 
neotions, end fresh improvement in his machi- 
nery, while the information which he ss scien- 
tist and machinist has to impact cannot but 
bo advantageous to the planters and to their fast 
advancing enterprise, which, nt this crisis in its 
history, needs all the help that experience, 
®^®''tifio research and improved appliances can 
allorn. We have had abundant proof that we 
have greatly underrated tho producing powers of 
our soil and olimato ; and while quantity is so 
rapidly increasing, ii is of the utmost importance 
that quality should bo kept up to the highest 
possible point. Thia is what Mr. Davideon is 
confident can be done by tho adoption of tho new 
method of drying the leaf, of whioh we have given the 
main principles, and whioh Mr. Davidson is ready 
and willing to explain in full detail. 
In justice to Mr. Jackson we feel bound to 
recall the fact that ho also has been addressing 
himself to the solution of the problem of drying 
tea at a lower temperature than baa been usual. 
In the deeoription of hia new machine, the 
“Britannia," it ia stated: 
At tho present time, approximately Iw'O-thirds of 
the left exported from Co>Ioii aud ludiA ia bciotc 
dried at a temperature of from 240 to 800 degrees. 
This high temperature is resorted lo, simply fo get 
tho work out of the maobiucs, the remit being that 
brokers and dealers, have from time to time, and 
are at the present moment, oommeuting on teas being 
high-fired, soorohed, and that they will not keep. In 
designing and experimenting with tho Britannia 
Dryers, whioh has occupied Mr.J'aoksou’s lime for dcbiIt 
two years, be has steadily kept in view the necessity 
or improving the tea, especially its keeping qualities, that 
tho teinperatuie at which the Brilsuuia Dryers should 
work, must not be higher than the tea will bear 
plant«« macbinofor an undue time, aud 
Tf “m ‘’I®® great importance 
of this. It will also be patent to all, that working 
SI the reduced temperature is esey aud prseti- 
cally obviates destruction of the air heating stove, 
V® improved aud durable principle, 
and poould require no repaira for many yeara, 
Alust Flautors will be able to appreciate the 
principle under whioh Tea Hollers work, i.e a 
charge of leaf is put in the machine, pressure is 
app led, and the machine is left to do the rest. The 
Britonma Dryers practically do tho same i-The 
fs ^ nut “in tht the endless web, 
tho rest furnace, aud the macbmes do 
removes all tedious attention 
.Dfytrs using trays, aud other drying 
surfaces requiring manipulation by hand, and' all 
mschhies know that automatio 
machines of all kinds are the best. The trays forming 
nivDto'd“orth«*^h‘“ »re individually 
hut°dn not follow each other oioscly 
but do not come m contact wiih each other or wiib 
any part of tbe machine whatever, oousequently there 
have tSo Tb® BrimunKet* 
coDtinuonsTv out'^rif ®0“®® 
^rmits con^Unt ^ chamber, whioh oot only 
* ™®mBtiiiB, but allowing tho web to 
contact ’ ‘“’J 
fo^tv^hoionofi**® Pryer ia a very powerful one, is per- 
of havina as muolfn®? 
dannor ^Th^ho^ bigbor velocity imparted to it without 
oinlf and a ““ »®lf-«djuBtiDg priu- 
oif os’caniim Wfl arrangement prevents waste 
^ 3 the cuds of tho bearing. The saving in 
first cost of one of these macbiuos,in labour to wo k 
pared with a number of small machines, but this is a 
seoonpry matter when compared with the far more 
important oonsipralion of obtaining nioe flavored, good 
keeping uniformly dried lea. 
