National Institute of France. 
@ast types. As to the process for imi- 
tating graving on copper, the following 
is what he says concerning itin the manu- 
script memoir already cited. The metal 
that he made use of to run or cast in his 
argile moulds being capable of yielding, 
by the help of strong pressure, the most 
delicate strokes of the types, he found 
out a method of making plates, which 
represented by hollow lines, as nan en- 
graving. the writing or the designs made 
on a plate of polished copper, discov ernug 
the least thickness left by the strokes that. 
he had formed with an earthy colour, 
when at the instant of cooling the plate 
of copper was pressed on the metal 
composition, The plate formed of this 
metal might. be printed in the rolling 
press like any other engraving. Ho fmann 
admits that this kind of graving is not 
without its ditficulties; and it appears to 
me, says the author, that he made but 
little use of it. 
Avout the year 1784, Hoffman laid be- 
fore the public the result of his method. 
A paper emanating from the Academy 
of Sciences, and bearing date March 13, 
1784 (and signed Le Roi, one of the mem- 
bers), contains the following notification ; 
‘“ We,” namely, the president de Sarron, 
M. Bailly, and myself, “having visited M, 
Hoffmann, at his apartments, at half past 
eleven this morning, we each wrote a 
sentence on a plate of copper which he 
presented to us, with some black ink that 
he had prepared. We delivered to hin 
the piate so written on, at - sixteen mni- 
nutes past twelve: in fourteen minutes 
alter, he returned us the plate, which he 
had been making use of in order to make 
another plate, calculated to print what we 
had written; and we effaced the writing 
of the first plate; in another quarter of 
an hour, he gave us a proof of our 
writing, which he had just drawn off; 
and this we now submit to the inspection 
of the Academy.” 
The proof is annexed to the note here 
transcribed. It is manifest, says the 
author, that the plate which served for 
the impression, was a plate hollowed or 
scooped in the manner of a graving on 
copper. The writing is dist: rauish- 
able and legible, but is, howev er, such as 
would be produced with thick and muddy 
ink. 
Annexed to the same note, says the 
author, appear two proofs of white writ- 
ing on a black ground. ‘This has, like- 
wise, been executed by means of a me- 
tal plate. The whigc strokes which re- 
627 
present the writing are neat and fine, 
and im the style of a good running hand. 
Nothing appears to indicate the method 
that Hoffmann employed in order to keep 
these strokes white, on a black ground, 
There is another page, 4to. size, which 
has a figure at the head and is intitled : 
bt Heliopt du Chevalier de Sorny, pour 
connoiire les longitudes en mer.” The cha- 
racters resemble those used in our print= 
ing-oftices, but they appear to have been 
traced by the hand, and polytyped, in or- 
der to obtain a hollow block in the mode 
of engraving on copper. The impression 
was certainly made with a metal form, 
by means of the rolling press, 
About the end of the year 1784, Hoff- 
main composed a prospectus of the. poly- 
type journal of Arts and Sciences, in 
which he announced that if the public” 
should give him due encouragement, he 
should have his journal ready for deli- 
very by the first of January, 1785. 
Hoffmann, father and son,bad obtained, 
about that.time, for fifteen years, an ex- 
clusive privilege of graving hollow and 
in relief, according tc the process of anew 
art; and in the month of January, 1785, 
they obtained some privilege for theirjour- 
nal; but they had much opposition to 
encounter on, the part of the copper- 
plate printers. Poreseeing, likewise an 
equal opposition from the letter-press 
printers, they addressed themselves to De 
Miromenil, keeper of the seals, and soli- 
cited from him a privilege similar to that 
of an ordinary printer, under the distinc- 
tive title of a polytype press. 
On receiving the memorial of the Hoff- 
‘imanns, the keeper of the seals consulted 
with a uumber of magistrates on the sub= 
ject; and when Vidaud de Ja Tour, coun- 
sellor of state, was afterwards appointed 
superintendant of the department relat- 
ing to books and booksellers, the keeper 
of the seals, by a letter bearing date Au- 
gust 17, 1785, gave him in charge to make 
trial of the prosess of theHoffmanns, and, 
on receiving from them the secret of their 
discovery, to deposit the same under seals, 
in the register’s office of the council. 
The two commissioners went to the of- 
fice of the Ifoffmanns on the 27th of Sep- 
tember, 1785; and on the 1st of October 
following, they transmitted a written re- 
port to the keeper of the seals. It ap- 
pos from this that the Hoffmanns had 
laid before them different prog 2 In writ- 
ing, in music, graying, and printing, as 
likewise, some part of-the preparations 
that Were necessary in the prucess, A 
4, smemoir 
