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1807.J 
pressure of the atmosphere, a difference’ 
which is produced by capillary action, 
The author points out two methods of 
sorrecting this maccuracy. The one is 
analytical, and the other, which will 
doubtless be preferred by the greater 
New Patents lately enrolled, 
ie ge 
number of observers, requires only an 
easy experiment, and a very simple cal- 
culation. By both of these methods, 
results more readily comparable may ba 
obtained. 
NEW PATENTS LATELY ENROLLED. 
a 
MIR. WILLIAM SPEERS’ (DUBLIN,) for a 
new Method of Purifying Fish Oil, 
and of applpng the Refuse to useful 
Purposes. 
Gin object of this invention is the 
refining not only of fish-oil, but of 
the oils obtained from all animal sub- 
stances, and also from expressed vege- 
tables. ‘The mode of performing this is 
by mixing the oil with an infusion of 
tannin. Mr, Speers recommends the 
tannin of oak-bark, but he says #my tannin 
whether natural from oak or other barks, 
or artificial, such as those described by 
Mr. WHatchett, in the Philosophical 
Transactions will answer the purpose. 
The mode which he prefers is the 
following: take equal quantities of oil 
and soft water; an the water infuse and 
agitate for a day ar two about one-tenth 
part of its weight of tanuin; itis then to 
be drawn off fine, and the oil and water 
to be mixed and boiled for some time, 
and then set by to cook The tannin will, 
by means of chemical attraction, unite 
with the gelatine or mucilage, and being 
heavier than oil will sink below it; but 
being lighter than water, it will swim 
above it; in other words, this refuse mat- 
ter will be found between the oil and 
the water. The oilis first to be drawn off 
and then the refuse matter may he ob- 
tained. This matter the patentee re- 
commends to be applied to the formation 
of cenients and stucco; or to the compo- 
sition of paints and varmishes; or to the 
composition of an excellent blacking for 
Jeather, which will by that means be 
made water-proot. 
Ea 
MR.. JOHN PpRosseR’s (HOLBORN,) for 
various Improvements upon Smoke Jacks. 
These improvements upon smoke 
or air-jacks, are as follow; that is 
tosay: Lhe firstimprovement consists in 
makiny the box, ease or body of the sin- 
gle smoke or air-jack, to extend to 
the whole Jength from or ear the céntre 
of the inside of the chinmey to the out- 
side or breast thereof, and inclosing the 
spindle, and terminating at or near the 
NMonrucy Mac. No. 161. 
chain-wheel. The second improvement 
consists in raising the said spindié and 
chain wheel, in a slanting direction, 
above the centre of the worm; by which 
the oil flows above the top carviage of 
the worm, without the assistance of pipes 
or tubes, the box, ease, or body, being one 
entire piece, except the top, which is 
screwed or fastened on to remove at 
pleasure, continued from or near the 
centre of the flue to the outside of the 
‘breast of the chimney, by which the oil 
put in the box, case, or body near the 
chain-wheel runs round, and incloses the 
whole work. The third improvement 
consists in making the chain-wheel of 
brass or iron, instead of wood, and of: 
.placing in the groove or space in which 
the chain runs, tags and holes, thereby 
effectually preventing the chain or chains 
from slipping. We have in the figures 
representations of the several parts, of 
which the improved box is called the 
compound and skeleton air-jack, because 
it contains various wheels, pinions, or 
cranks, connected with the first worme 
wheel, or the axle thereof, and continued 
any length asthe situation of the chimney, 
flue, or place in which it is intended to 
be fixed, may require. It is called ske- 
leton, because the body may be made 
nearly as small as two inches wide, by 
from four to eight or twelve inches deep, 
and it is called an air-jack, because, like 
the others, the air is more the first 
moving pawer than the smoke. The fly 
may be made to any size according to 
the flue. The advantages of this form of 
the box are great, and are as follows 
Suppose the jack is fixed in a very stall 
flue, or in the fimmnel of a ship’s stove, 
then, in the usual way, the body of the 
old jack almost fills up the fiae or fannel 
crossing it, beg from nine to twelve 
inches wide in the box, and thereby 
preventing the fly from being easily taken 
up and down, atid greatly checking the 
draft, whereas in this it is the reverse: 
the box, case or body, being made as 
narrow as two inches, a trifle more or 
less, ane continued en frem or near the 
Aa gentre 
