244 
quires removal in this way every three or 
tour weeks, though it increafes the wear 
of the pans. 
The fecond article in this fpecification 
is the ufecf alkalies added to the b:ine in 
certain quantities, in order to decompofe 
the earthy-falts, and to render the falt 
purer. Any*kind of fixed alkali is pro- 
pofed by the Patentee, but no particular 
direStions are given for their ufe by him, 
as both the time of adding them, and the 
quantity (he obferves), muft depend on 
the nature of the particular brine ufed, 
which differs much in different parts. 
The third article is an ingenious con- 
trivance for enabling the manufa&turer to 
detain the fire under any pan,-by uling cir- 
cuitous, inftead of fraight, flues. Several 
falt-makers ‘have formed thefe circuitous 
or zig-zag flues, through which the fame 
of the furnaces has circulated very well 
till the brine began to boil; after which, 
the motion given to the pan hy the violent 
ebuillition, has always fhaken and lifted up 
the pan, with all its contents, to a degree 
fufficient to raife it off the flue-walls, and 
thus to defeat the obje&t of the circuitous- 
flues, by allowing the flame to pafs ftraight 
on to the chimney through the {pace left 
by the heaving of the pan. 
This is remedied by the Patentee, by 
fixing into the bottom of the pan long 
iron-plates bent through their length at 
right angles, fo as to form ene flat furface 
to be laid on the pan, and there fixed by ri- 
vets, or any other mode, whilft the other 
part of the plate hangs down perpendicu- 
sarly, and is received joofely into a -groove 
in the bricks of the circuitous. fiue-walls. 
By this method, the lengthened courfe of 
the flame may {till be preterved. 
(We underftand that this patent-right is 
difpofed of to fome falt-manufacturers at 
Northwich). 
eS ee 
MR. LANE, of Lincoln’s Inn-[quare, Lon- 
don, for GR&aDUATED MEASURING- 
GLASSES. 
IT has been confidered as a great im- 
provement in the manual part of pharma- 
cy, both for neatnefs and accuracy, to fub- 
ftitute, for the old pewter-meafures, glafles 
gracuated from two or more ounces 
di wawards to as {mall a quantity as is 
ever prefcribed, except in the form of 
drops. Herce we now find no apotheca- 
ry’s ficp unfurnifhed with thefe glaffts, 
which are in conftant and daily ufe. How- 
ever, 2s no uniform ftandard of meafure- 
ment has been reiorted to, great imaccura- 
- cy in the graduation has crept into ufe, 
from the ignorance or carelelinefs of the 
lew Patents enroiled. 
‘[O@ober 1, 
makers. This the refpeCtable Patentee, 
and inventor of the prefent correéted mea- 
fures, had opportunity of alcertaining, 
when Warden of the Apothecaries Com= 
pany, and it determined him to adopt the 
plan here given. ‘* The weight of.a gal- 
lon of diftilled water is to be afcertained m 
troy-grains, whether of wine or beer mea- 
fure,whereby,either by addition or divifion, 
the proper proportion of all the graduations 
requifite for any meafure may be known in 
troy-grains, and parts of a grain, by hav- 
ing weights and {cales adapted to the va- 
rious purpofes. To meafures having a 
large furface, the furface is needful to be 
attended to, and the inaccuracy arifing 
from thence is to be correéted by marks 
added to dire&t the eye to the fame Jevel as 
when they were firft graduated. When 
made with glafs, two furfaces being feen 
through glafs containing tran{parent fluids, 
divifions are to be made correfponding 
with the upper and under furfaces if re- 
quired. When lines are required for ad- 
ditional accuracy, the marks will ferve as 
a guide whereby they may be deferibed. 
When glafs is not beft adapted to the ufes 
for which graduated-meafures may be 
wanted, they are to be made of other fub- 
ftances.”’ i 
The Patentee, we find, has even at- 
tempted an accurate meafure for dividing 
a portion of te wine-ounce into parts cor= 
refponding with what are confidered as 
drops. He juftly obferves that drops are 
very unequal, the fame liquid being ufed, 
when falling from unequal furfaces ; and 
alfo vary from different liquids. This is 
certainly true; yet the latter circumftance 
‘is apparently of little confequence, fince 
the practitioner, in ordering fo many drops 
of any liguid, does not confider 
much of the liquid zz weight he wifhes to 
give, but orders the drop, as a mode of 
divifion with which he is familiar, which 
is all that is wanted, could the equal fize of 
the drop be always fecured. We know 
not how the Patentee, in attempting to 
meafure out from a very minute vefiel fo 
minute a quantity as a few drops (for, as 
he informs us, he has conftru&ted meatfures 
from drops to pints, in veflels of refpective 
fizes), has been able to make an accurate 
allowance for that portion which muft al-_ 
ways adhere to the fides of the veffel, and 
which, in fuch cafes as thefe, muft bear a 
confiderable proportion to the whole: but, 
not having a fuil defcription of the whole 
apparatus, we cannot give any opinion 
withregard to the fuperiority,in this refpect, 
to the ufual method of meafuring drops, 
corrected by the improyement which we 
4 believe 
how | 
— a ee, 
oe ae ee Te 
