282 
tHE TROPICAL 
AGRICULTURIST. [Oct. 1, 1899. 
works a necessity. Apart from their use as ad- 
juncts of tea machinery there is a great 
demand for 
" SIROCCO " FANS 
in nearly every department of the industrial world. 
The illustrations of these Fans are accompanied 
by particulars of surprisinr; trial tests. The lead- 
ing features of this new departure are concisely 
described in the catalouge before us by the follow- 
ing comparison between the centrifugal fans at 
present familiar to us and Davidson's patent. 
Under the former wc find as the hitherto 
accepted data for best construction : 
" Blades. — Comparatively few ; radially deep ; outer 
edges short axially, and either straight or curved 
backwards from direction of rotation ; ends unclosed 
their full depth, from the outer to the inner edges ; 
and the inlet opening for admitting the air to the 
centre of the fan approximately one-half of the fan 
diameter ; it having been accepted as an axiom 
that a small inlet (although detrimental to volume) 
was necessary for pressure." 
In the " Sirocco " Fans, the construction 
above referred to is practically reversed on every 
point, viz ; — 
" Blades. — Very numerous ; radially very shallow ; 
outer edges long axially, and curved forward in the 
direction of rotation ; ends open towards the inflowing 
air, from the outer to the inner edges ; and the inlet 
opening for admitting the air to the fan, of approxi- 
mately equal diameter to that of the fan itself, where- 
by in the " Sirocco " fan maximum volume is com- 
bined with maximum pressure, which combination 
has not been obtained in any other fan hitherto 
made." 
Mr. Davidson has thus evidently inaugurated 
a new and important change in the entire prin- 
ciple of construction of fan blades, and also as 
regards the inlet opening for the air, which in the 
"Sirocco" fan is about four times larger 
in area (relatively to the diameter of the fan) 
than in centrifugal fans as generally made ; 
whereby the frictional resistance to the inflow 
of a given volume of air is only a sixteenth of 
what it is in other centrifugal fans. With his 
usual objection to half measures and premature 
disclosures of experimental work, Mr. Davidson, 
before making full announcement of his revolu- 
tionary discoveries in connection with the opera- 
tive principles pertaining to fan construction, 
satisfied himself in the most thorough way as to 
the results. The catalogue before us contains data 
on the subject of "Sirocco" versus other centri- 
fugal and propeller fans which testify not only 
to the thought and labour necessary in the pro- 
cess of evolving practical issues from theory, but 
demonstrate the remarkable success achieved. 
One result not mentioned in the catalogue is that 
Mr. Davidson has 
SUCCESSFULLY VENTILATED 
several of the Courts in the Koyal Courts of J us- 
tice, and has lately received tlie order to similarly 
ventilate a further number of them. Many other 
systems for the ventilation of these Courts have 
been tried and found wanting, and Mr. Davidson's 
success is in itself a convincing proof of the eliiei- 
ency of his new fans. 
It is not to be wondered, therefore, that 
"A PHENOMENAL DEMAND " 
lias already arisen for " Sirocco " Fans, and that 
the Patentee is making ariangements on an ex- 
tensi^e scale to meet this demand. We wish 
every success to his new invention, which seems 
destined in the wide field of engineering to which 
it applies to rapidly develop into a more exten- 
sive business than his now large and highly suc- 
cessful business in Tea machinery; but we at 
» 
the same time hope that this developTuent may not 
involve a lessening of his interest in, or withdiawal 
of his inventive abilities from, the further de- 
velopment of machinery for Tea manufactujje, 
which would be a serious loss to the Tea Planting 
industry.— Jf. <£■ C. Mnil, Sept. 1. 
CEYLON TEA IN GERMANY. 
THE YEAR AT HAMBURG. 
Business in tea at Hamburg was limited, last 
year to aliout the same extent as in 1897. It is 
considered that the mild autumn and winter of last 
year were unfavourable to the increase of tea con- 
sumption in Germany and Austria. The importa- 
tions of Indian and (Jeylon teas were, however, 
in excess of those during 1897, and the consump- 
tion of these sorts appears to be developing, 
though slowly, in Germany. It is thought that 
the present eilbrts towards exploiting and de- 
veloping the resources of China are likely to lead 
to the resuscitaton, by European assistance, of the 
cultivation and export trade of Chinese teas at a 
near date.— P^anifc*', Sept. 16. 
The Shipment of Tea-Chests.— The Cap- 
tain of tlie "Clan Macdonald " makes a 
small, but very useful appeal to planters to 
mark as "top "one of the non-morticed sides 
of their tea-chests — a practice which Messrs. 
Freudenljerg are in the habit of doing. If 
this wtre done in the factory there M'ould 
be a trifle less of the " loss in transhipment " 
which the draft-allowance is still held to 
account for in part. 
TuK Pearl Fisheries of the Dutch East 
Indies, — A report by the United States consular 
agent; at Macassar, in the Celebes, on the pearl 
lisherios in the Dutch possessions in the Eastern 
Archipelago, has been issued by tlie Department 
of State in Washington. The shells of the pearl 
oyster form one of the mo-t imnortant exports 
from Macassar ; anil, up to the beginning of the 
present decade, they were sought almost exclusively 
by natives who lished in the shallow water of 
the bays without using a diving apparatus. In 
1893 a Loudon company sent a schooner, with 
some luggers to the Aru Islands to try fisliing 
in deep waetrs ; but the little fleet was compelled 
to leave the Archipelago in consequence of a law 
that only vessels under the Dutch flag, owned by 
Dutch subjects or companies, should be allowed to 
engage in pearl fishing. Kesideuts in the Eastern 
Archipelago now began to give more attention to 
the fisheries, and Europeans, Chinese, and Arabs 
made arrangements with native chiefs in whose 
waters shells were supposed to be, by which a rent 
or royalty was paid for the right to fish. At pre- 
sent fishing is prosecuted on the east coast of the 
Aru Islands, on the east of New Guinea, off Celebes 
and Timor. The chief market for the shells is 
Paris, Loudon and other Continental cities taking 
but small quantities. 1 wo hundred and fifty tons 
were exjiorted from tlie Dutch East Indies in 
1897, and the quantity is increasing. Aru shells 
sell at £140 a ton, those from New Guinea, 
Timor, and Celebes fetching from £80 to£)00 a 
ton. The regulations permit of fishing all the 
year round, but, in fact, the monsoons prevent this. 
Natives of the Philippines are mostly employed 
on the work as they are better than those of the 
islands close to the fisheries. A cheaper kind of 
shell is also fished largely, and is sent to Ger- 
many and England where it is used in the 
manufacture of buttons.— London Times, Aug. 29, 
