1802. ] 
without inconvenience two hours, during 
which a confiderable quantity of work 
may be performed with regard to ftopping 
leaks, &c. 
ETE 
MR. THOMAS SAWDON’S (LINCOLN) 
Sor @ MACHINE for CUTTING STRAW 
for FODDER for CATTLE, 0” PRINCI- 
~ PLES entirely new. 
This machine is worked by hand. A 
man turns a wheel four feet in diameter, 
this gives motion to a wooden roller, in- 
laid with ribs of iron, and to one made 
of caft-iron; by the operation of thefe 
the hay or ftraw is drawn from the box to 
the knives, of which two or three are 
fixed upon an iron axle, and are of courfe 
turned round with the motion of the 
wheel, and are made to cut again{t a-plate 
of polifhed fteel. 
Obfervation.—T he particular principles 
of this machine, by which it is diftin- 
guifhed from other ftraw-cutters, made 
upon plans fomewhat fimilar, cannot be 
explained without reference to the draw- 
ings which accompany the fpecification, 
NREL SUMED, 
MR. WILLIAM WALMSLEY’S (MAN- 
CHESTER) foraMACHINE /or BATTING 
and OPENING COTTON-WOOL, SHEEP S- 
WOOL, TOW, HEMP, and FLAX. 
The Patentee has given with his fpe- 
cification a bird’s-eye-view, a fide-view, 
and an end-view, of his machine; by 
thefe, and a careful attention ‘to his de- 
{cription,- the mechani¢ and manoufac- 
turer will be able to eftimate the value 
and importance of the invention. 
— aie 
LORD DUNDONALD's, for @ METHOD or 
METHODS Of preparing a SUBSTITUTE 
Or SUBSTITUTES for GUM-SENEGAL, 
and other GuMs, extenfively employed 
tn cerlain BRANCHES of MANUFAC- 
TURE, 
Lord Dundonald’s invention confifts in 
precuring a fuftitute for gum from the 
clafs of plants called in botany lichens ;— 
from the plants of hemp and flax, pre- 
vioufly to being fteeped in water, or after 
having been fteeped ;—likewife. from the 
bark or rind of the willow or lime-tree. 
The firft procefs in preparing gum from 
the lichen is to free it of the outer {kin of 
the plant, and the refinous matter, which 
is done by fcalding it two er three times 
in boiling water, or by aétually boiling 
it for fitteen or twenty minutes, then 
wafhing it in cold water, and laying it af- 
terwards ona ftone or brick-flgor for ten 
or twelve hours, 
New Patents lately Enrolled. 
443 
The fcalded lichen is then to be put 
into a copper boiler, with a due propor= 
tion of water, that is, about two wine- 
gallons to every pound of lichen, and 
boiled during ten or twelve hours, adding 
about a quarter of an oynce of foda, or 
pearl-afhes, for every pound of lichen, 
or, inftead of thefe falts, about two 
ounces of volatile alkali. The boiling 
fhould be continued until the liquor ac- 
quires a confiderable degree of gummy 
confiftence: it is then fuffered to drain, 
and after to be {queezed in a prefs fimilar 
to that ufed by the melters of tallow. 
The firit boiling does not extract the 
whole of the gum, and fhould be repeated 
a fecond and even a third time, diminifh- 
ing, at each time, the quantity of water 
and the quantity of alkali: but when the 
volatile alkali is made ufe of, the boiler © 
muft be made of iron, inftead of copper, 
which is acted upon by the volatile alkali. 
Hemp, flax, and the bark of the wil- 
low and lime-trees, or fea-weed, are to 
be heated in a fimilar manner, to extrack 
the gum or mucilage contained in them 3 
and his Lordfhip includes in this Patent 
every tree, plant, or vegetable, of what- 
ever kind, from which a gum is to be ex- 
tracted by the aétion of volatile or fixed 
alkaline falts, when ufed in the procefles 
of maceration, digeftion, or boiling thefe 
vegetable matters. 
Obfer-vations.—It does not appear, from 
the trials made by Lord Dundonald, that 
there is any very great difference in the 
produce of gum from the lichen, colle&ted 
from different trees or flirubs ; all of which 
anfwer egually well for yielding a gum 
fit for calico-printing. The lichen is 
moft abundant on trees that grow on a 
poor {tiff clay foil, particularly if Gtuated 
at fome confiderable height above the level 
of the fea. It fhould be pulled in very 
dry weather; and if a fufficient quantity 
of it is not to be found in this country, 
it may be had in unlimited abundance 
from Norway, Sweden, and the northern 
parts of America, where it grows from 
twelve to eighteen inches in length, de- 
_prefling the branches of the tree by its 
weight. 
The lichen does not confift entirely of 
agummy matter; there is an outer fkin, 
below that a green refinous matter ; and 
the remainder of the plant confilts partiy 
of gum, partly of fomething analogous to 
animal fubftances, and a {mall proportion 
of fibrous matter, which cannot be dif- 
folved by boiling, or the action of alka- 
ling falts. 
MR 
