which have hitherto been afcertained by 
computation, inftead of infpection, as is 
to be done hy Mr. Speer’s improvement. 
On the upper end of the face are marked 
the figures 35, to denote that the gradua- 
tions on that face of the prifm are appli- 
cable to fpirits at that temperature. On 
the contiguous faces the fame is done for 
different temperatures, as 40°, 50%, 60°, 
and 70°. ‘Ihe number of fides of the po- 
lygon may be greater or lefs, according to 
the number of temperatures ; but the Pa- 
tentee recommends cight fides, as the belt 
adapted for the general purpofes of reve- 
nue and commerce, beginning with 35°, 
andending with 70°. To prevent any 
error in reading off the ftreogth upon a 
wrong face of the inffrument, a final] flid- 
Mosk: Va ; 
ing-iniex is applied to the flem, and. 
which points out the proper divifion. By 
the addition of other indexes, the 
ftrengths of the intermediate temperatures 
are obtained, Thus if the temperature be 
s0°, nothing farther is required than to 
place the index No. 1. on the fide marked. 
50°, and immerfe it in the fluid, of which 
it will at once fhew the ftrength ; but if 
the temperature be 51% or 52%, the next 
lighter index, No. 2, is to be uled, which 
will caule the graduations to indicate 
ftrengths for the temperature 512° ; but 
if the temperature be 53° or 54°, the in- 
dex No. 3 being applied, the faid face 
would (hew the ftrengths for the tempera- 
ture 534° ; fothat the refule by the in- 
ftrument will be true for the intermediate 
semperatures within half a degree; and 
even this fmall difference may be obtain-- 
ed by holding the jar containing the fpirit 
a few moments in the hand. 
a Tee 
MR.» THOMAS WILSON’S (BISHOP-WEAR- 
MOUTH) for uniting, combining, and 
conneGiing, the METALLIC PATENT 
ELOCKS of ROWLAND BURDON, jor 
the Confiruction of ARCHES. 
Inftead of uniting the blocks by bar- 
iron on the outfide of the arms and bolts 
faftened with cotterels or forelocks, as 
defcribed in Mr. Burdon’s fpecification, 
Mr. Wilfon’s method is to infert dowels, 
or flots, into the ends of the arms of 
blocks at the points of bearing, and to 
bring the blocks into clofe contact, by driv- 
ing wedges through the blocks and dow- 
els, or flots, thereby combining the com- 
ponent parts of each rib ina more firm 
and fubftantial manner than has heretofore 
been practifed, and confiderably diminifh- 
ing the draft or thruft of the arch.—Se- 
’ proof; and it is faid to be 10 per cent. under 
proof when 100 gallons of fpirit contains 10 
gallons more of water than the fame quantity 
of proof-{pirit contains. 
New Patents lately enrolled. 
4G 
condly, inftead of connecting and combin-~ 
ing the ribs by means of hollow tubes, 
Mr. Wilfon introduces crofs-bars from 
rib to rib, between the blocks, at the 
points of bearing, with apertures of fuf- 
ficient fize to admit the dowels, or flots, to 
pafs through the fame; by which means 
the ribs are keptin their required pofition, 
and the blocks do not bear againft each 
other, but are kept in clofe contact with 
the crofs-bar againft which they abut, and 
are connetted together by the dowels, or 
flots, and wedges. . 
=e 
MR. EDWARD STEPHENS’S (DUBLIN) 
for AFURNACE-STOVE Of FIRE-PLACE 
that can be convenient.y applted to the 
BURNING of LIME-3TONE; at the 
fame time that it is ufed for Heating all 
manner of Corn-kilas, and Drying. 
houfes for Malt, &c.; and applicable to 
the making of Coke, fmelting Metals, 
beating Boilers, and other like Purpofes. 
The invention here claimed extends one 
ly to the furnace and air-chamber, with 
appendages which cannot be explained 
without the afliftance of engravings. It 
is proper to fay, that every aperture in the 
walls or roof of the kiln muft be clofed, 
that admit cold air either under or over 
the corn, except the opening round the 
furnace, and that through the fteam-paf- 
fagein the roof. The furnace, when uled 
as a drying-houfe, aéts by conveying 
through the article to be dried a ftrong 
current of pure atmofpheric-air, heated 
to the degree required to produce the ef- 
fect. 
When the fire-place is adapted to the 
heating, boiling, or evaporating any ‘li- 
quid, or to the heating of reverberating 
furnaces, ovens, &c. thedirett flame may 
be firfapplied to their ufe; and having 
exerted ‘its influence there, the remaining 
heat is afterwards taken up by the pipes 
placed diagonally in the fire-flue, or chim- 
ney, which may be either upright or he 
rizontal. 
This invention confifts not only in the 
conttruction of the furnace, but'in the me~ 
thod of procuring a trong current of heat- 
ed-air, and taking up nearly the entire re- 
{ult of the fuel. before it can efcape out of 
the chimney-top, and alfo in the applica« 
tion of an air-chamber, which a&ts without 
a valve, regifter, or damper, and a fire- 
place that reyuires but little or no expence 
to keep it confantly at work, being adapt- 
ed to the effeétual burning of lime and 
cheap fuel, which, when burned, can be 
oceafionally drawn out without ftopping 
the procefs, or injuring the ignited fuel 
remaining in the fiie-place. 
MONTHLY 
