List of Patents. 77 
lag slate^ grinding it very fine, and mixing with it as 
much ivory-black as will turn it to a fine black colour. 
When it is thoroughly dry, you may write on it with a 
slate pencil, or black or red lead. In witness whereof, 
&C. 
NO. 17 . 
List of English Patents.* 
(Continued from vol. 1, page 480.) 
1797. 
John Manton, April 12, invention or improvement in the construc- 
tion of guns and pistols. 
Rob. Cross, April 26, a new invented tan-pit, and mode of tanning. 
T. Todd, May 9, an hydraulic pump or machine for raising water. 
Richard Varley, May 29, a perpetual moving-power. 
Timothy Harris, July 4, method of manufacturing pins, with iron 
and other metals, and making the same white. 
Joseph Slater, July 4, improvement in a machine for finishing 
bleached, dyed, and printed muslins. 
Anthony George Eckhardt, July 4, method of making draw or 
bench looms, for manufacturing carpets, borders, and other things. 
John Hawksley, July 4, method of combing wool, cotton, silk, 
flax, hemp, and mohair. 
John Maule, July 4, improvement on a machine for cleaning 
grain from the straw. 
John Richardson, July 4, machine to be applied to glasses and 
pebbles of every description, for the use of sights in general. 
Henry Johnson, July 7, a water-proof compound, and a vegetable 
liquid for bleaching, whitening, and cleansing woollens, linens, cot- 
tons, See. and also for preparing stuffs or cloths made of wool, linen, 
cotton, or silk, in order, by the application of the aforesaid water- 
proof compound, to render them impenetrable to wet. 
Archibald, earl of Dundonald, Aug. 1 6, method of preparing ce- 
ruse, or white lead, which he conceives will be of great public utility, 
particularly as he has reason to believe it will not be injurious 
to the health of persons employed therein. 
Anthony George Eckhardt, Aug. 18, method of constructing 
Repertory, vol. viih 
