MO Intelligence , 8£c, 
Mr. Hen*, an eminent tanner at Srzensk, in Poland, has ascer- 
tained that the leaves of the oak may be advantageously subsituted 
for the bark, in tanning leather, provided they are used in the 
month of September, when they possess the bitter sap which they 
afterwards lose. > ; Tilloch , M2 159. 
To make a common watch into a nocturnal one, Mr E. Walker 
of London, “ made notches with a hie in the rim of its inner case, 
against every hour upon the dial, except 3, 6, 9, and 12. These 
tangible marks are made no deeper than just to receive the nail of 
the huger or thumb, as it is drawn over them. The hour of 12 is 
known by the pendant, and little pins are hxed into the case at the 
hours of 3, 6, and 9, proj cting outwards about one-twetieth of an 
inch, to distinguish those hours from the rest. 
To ascertain the time in the dark by this watch, open the glass, 
and feel with the finger the situation of the hour hand, and correct 
the tangible marks, beginning at 3, 6, 9, or 12, to hnd the hour; 
and by the same means the minutes are found. 
Mr. W. considers it as giving the time with more precision than 
a repeater, and without disturbing the repose of any person near 
it. Tilloch , JYo. 167. 
PREPARATION OF BRUNSWICK GREEX. 
Kasteleyn has lately published the following method of prepar- 
ing this colour, which is much used on the Continent for oil paint- 
ing, and in the manufacturing of printed paper. Shavings of cop- 
per are put into a close vessel, and besprinkled with a solution of 
the muriat of ammonia. The metal first unites with the muriatic 
acid, and is dissolved, and is in its turn precipitated by the disen- 
gaged ammonia, to which it now joins itself. The precipitate is 
then washed and dried in wooden boxes, or upon an extended 
cloth. The liquid which remains, as well as the water of the first 
washing, may be employed several times in succession for new 
operations, by dissolving in it fresh portions of sal ammoniac to 
the point of saturation. Three parts of the muriat of ammonia 
are sufficient for two parts of copper, and the result is six parts of 
colour. This beautiful green is in Holland called Friesland green. 
It is almost always adulterated with ceruse. Tilloch , vol. 4. 
CEMENT FOR FILLING UP CRACKS AND FISSURES IN IRON VESSELS. 
The same author has also made known this cement. It consists 
of six parts of yellow potter’s clay, one part of the filings of iron, 
and a quantity of linseed oil sufficient to form the whole into a 
paste of the consistence of putty. Tilloch , vol, 4. 
