630 
periments on the mode of polytypage, by 
graving, and also attempts in stereoty- 
page. Among these, Gingembre, who 
commenced his first attempts in 1789, 
deserves honourabie mention. One of his 
operations, whichour author considers as 
a real discovery, was the multiplication of 
plates imitating those graven on copper. 
By this means he was enabled to obtain 
from asingle plate, hollow-graved, or bit 
in,a number of plates, also hollow-grav ed, 
and allidentical. The following was the 
method which-he adopted. He caused a 
head, viz. that of Ceres to be engraved on 
aw steel plate. After the engraving was 
executed, the steel was tempered. He 
then prepared a copper-plate, hardened 
by the mixture of a sixteenth of platima, 
but afterwards made also use of copper, 
hardened, by any other mixture, and by 
beating cold. The copper-plate, when 
laid on the steel-plate, being submitted 
to the action of a screw-press, the result 
was, that the copper yielded in relief, 
the strokes bitten-in on the steel. Ha- 
ving then prepared some plates of mol- 
ten copper, or red brass, and having laid 
them on the hard copper-plate, he in- 
troduced the two plates laid together be- 
tween the rollers of the flatter, taking 
evcry necessary precaution that the 
pressure might be equal in every part. 
By this method, he procured as many 
plates or forms, whether prominent or 
bitten-in, as he could wish. Gingembre 
peor coe his method to Herhan 
and to Meunier, who shortly afterwards 
made use of it mn the fabri cation of as= 
sienats. It would be a curious and in- 
teresting speculation to notice the aggre- 
gate of experiments in different kinds, 
that ingenious artists had recourse to, 
with aview to effect the fabrication of 
assignats. A power which nothing 
could then resist, issued out its orders; 
men of the greatest repxtation in the arts 
and sciences were invited to give their 
ideas on the subject ; ai were heard who 
had any pretensions respecting any 
newly-discovered means aes perfecting 
the fabrication of the assignats, for ac- 
elerating it, and for rendering ohio in- 
capable of imitation ; and their proposi- 
‘si were forthwith ihe ted to exa- 
mination and to trial. The contingent 
expences were not at ail considered, as 
the creators had in their own hands the 
means of establishing the funds from 
which the expences were to be disbur- 
sed. The rapidity of the movement form- 
ed the only obstacle that seemed capa- 
ble of impeding the success; but this 
rapidity. was compensated by the facili ty 
a 
National Institute of France. 
aac arkiitoes ela means were multiplied. 
The fabrication of assignats gave rise to a 
multitude of happy discoveries and ex- 
_periments, relative to the manufacture 
of paper, to the mechanism of printing, 
to the ink used in it, to engraving, and 
the tempering of ne dies, and of the 
puncheons; she memory of which disco- 
veries, says the author, will, in all pro- 
bability, never be lost. 
The author then proceeds, with a view 
to illustrate the two subjects which he 
has undertaken. to investigate, viz. polyty- 
page, as it relates to the. method of 
graving in copper, and stereotypage, as it 
relates to the method of printing with 
characters, to give an historical detail, 
tracing the first fabrication of assignats, 
‘and the impertectious which experience 
soon detected in it. 
After this doseriptive sketch, the au 
thor takes notice that Louis Etienner 
Herhan, Firmin Didot, and Nicolas 
Marie Gatteaux, obtained each, we- 
spectively, patents for the imvention 
from the government of that time. 
Herhan’s patent is dated the 8d Nis. 
vose, year sixth, and it is granted to him 
in consideration of a petition from him 
bearing date the fifth Frimaire preceding. 
The preamble of the patent announces — 
a new method as described in the, petiz 
tion of casting solid forms, which me- 
thod was invented and completed by 
the petitioner, in the month of Messidor, 
year fifth. He had remarked that solid 
plates, fabricated by a nuinber of artists, 
only produce secondary moulds ‘from 
moveable types, aud yielded imperfect 
and expensive results, | The petitioner 
then declares, that he has invented an- 
other process, which consists—First, in 
making moveable chavacters, graved or 
bitten-in, 1a lieu of being im relief— 
Second, in composing with ‘these charac- 
ters, pages that form a matrix; and 
third, im taking off a cast from this ma- 
trix. - Conforn iably to the tenor of this 
petition, a patent was granted to Herhan, 
authorizing him to fabricate, use, and 
vend, during the term of fifteen years, 
solid forms calculated for printing agree- 
ably to the method. described in the pe- 
tition. 
The patent of Firmin Didot, is ‘ dabeg 
- 6th Nivose, and empowers him to cone 
struct, during the term of fifteen years, 
stereotype forms, and to publish works 
from them. 
The patent of Gatteaux, is dated 
twenty-ninth Pluviose, and the-term of it 
rans for five yeers. In this, Gatteaux 
declares hims elf the inventor ofa method 
4 . 
