THE Commercial and Agricultural Magazine.

No. XXVII.) OCTOBER, 1801. POL VE

WE—— Ere

di For the Commercial and Agricultural Magazine. MACHINE FOR LAYING ETCHING GROUNDS. Invented by Mr. G. TERRY, Engraver to the Bank of England,

HIS plate repreſents the Machine invented for the uſe of Engravers, for the purpoſe of laying grounds on their cop- per-plates before etching on them.

Some of the inconveniences to which they have hitherto been ſubjed, ſuch as that of having their grounds irregular, or too hard, or ſoft, through exceſs or want of due heat, irregularity of co- lour; duft, partial thickneſs or thinneſs, through hurry or want of proper means for holding the plate during the operations, are removed by the uſe of this machine; which, by means of a ſmall or large external lath ſhifting frame, may be accom- modated to plates of various ſizes.

No. 1. repreſents a table on which two fire pots ſand for heating the plate.

2.‘The two fire pots, made of caſt iron, according to the new principle now uſed for copper-plate printing.

3. Four blocks, two inches above the fire-pots, to receive a caſt iron plate, for equalizing the heat to the copper-plate.

4. Two laths, with eguidiſtant holes,‘on which an external and internal frame flides up and down, containing the copper- plate: the internal frame to which the plate is faſtened turns on two center pins, and is ſtopped by the pia in the front.

5. The internal frame turning on centers,

6. The external frame, which ſlides. up and down the twa laths, ſuſpended by cords and pulleys.

7. Center pins of the internal frame,

8. A pin, which paſſes through the external ſliding frame inta the internal frame, ſtops it from turning round,

9. Cords for raiſing the two frames up or down.

Io. Two holes at the top of the lachs, through which the cords paſs, by which the frame hangs.

11. Equidiſtant pin holes to the laths to ſtop the frame higher or lower as may be wanted, according to the heat of the fire. 7

12. Pins for the holes in the laths for ſtopping the frames on the laths,

13. Pulleys for the line.

14. Iron weight equal to the ſliding frame, to keep the plate ſtationary till faſtened with the pins.

Coun.© dg. Mag, Val. V.(C