THE YOUNG 
SCIENTIST. 
Olive-green results from making the 
surface black by means of a solution of 
iron and arsenic in muriatic acid, polish- 
ing with a black lead brush, and coating 
it, when warm, with a lacquer composed 
of one part lac varnish, four of turmeric, 
and one of gamboge. 
A steel-gray color is deposited on brass 
from a dilute boiling solution of chloride 
of arsenic ; and a blue by careful treat- 
ment with strong hydrosulphite of soda. 
Black is much used for optical brass 
work, and is obtained by coating the 
brass with a solution of platinum, or with 
chloride of gold mixed with nitrate of tin. 
The Japanese bronze their brass by boil- 
ing it in a solution of sulphate of copper, 
alum and verdigris. 
Success in the art of bronzing greatly 
depends on circumstances, such as the 
temperature of the alloy or of the solu- 
tion, the proportions of the metals used 
in forming the alloy, and the quality of 
the materials. The moment at which to 
withdraw the goods, the drying of them, 
and a hundred little items of care and 
manipulation, require attention which 
experience alone can impart. 
To avoid giving any artificial color to 
brass, and yet to preserve it from becom- 
ing tarnished, it is usual to cover properly 
cleaned brass with a varnish called " lac- 
quer." To prepare the brass for this, the 
goods, after being annealed, pickled, 
scoured and w^ashed, as already ex- 
plained, are either dipped for an instant 
in pure commercial nitrous acid, washed 
in clean water, and dried in sawdust, or 
immersed in a mixture of one part of 
nitric acid with four of water, till a white 
curd covers the surface, at which moment 
the goods are withdrawn, washed in clean 
water, and dried in sawdust. In the first 
case the brass will be bright ; in the latter, 
a dead flat which is usually relieved by 
burnishing the prominent parts. Then 
the goods are dipped for an instant in 
commercial nitric acid, and well washed 
in water containing some ,argol (to pre- 
serve the color till lacquered), and dried 
in warm sawdust. So prepared, the goods 
are conveyed to the lacquer room, where 
they are heated on a hot plate and var 
nished. 
The varnish used is one of spirit, con- 
sisting, in its simple form, of one ounce 
of shellac dissolved in one pint of alcohol. 
To this simple varnish are added such col- 
oring substances as red sanders, dragon's- 
blood, and annatto, for imparting richness 
of color. To lower the tone of color, tur- 
meric, gamboge, saffron, Cape aloes, and 
sandarac are used. The first group red- 
dens, the second yellows the varnish, 
while a mixture of the two gives a pleas- 
ing orange. 
A good pale lacquer consists of three 
parts of Cape aloes and one of turmeric to 
one of simple lac varnish. A full yellow 
contains four of turmeric and one of an- 
natto to one of lac varnish. A gold lac- 
quer, four of dragon's-blood and one of 
turmeric to one of lac varnish. A red, 
thirty-two parts of annatto and eight of 
dragon's-blood to one of lac varnish. 
Lacquers suffer a chemical change by 
heat and light, and must therefore, be 
kept in a cool place and in dark vessels. 
The pans in use are either of glass or 
earthenware, and the brushes of camel's- 
hair with no metal fittings, — Ironmonger's 
Eeview. 
The Heavens for July. 
BY BEELESr H. WEIGHT. 
Mekcury will be brightest July 24-27, being' 
an evening star and setting as follows : 
July 20— 8h. 4:0m. evening. 
" 25— 8h. 31m. 
" 30— 8h. 17m. 
This will not be a favorable opportunity to ; 
observe this planet, owing to its slight altitude 
at sunset, and the long duration of twilight. 
Venus will be very close to Uranus July 8, in 
the evening, being about one-fourth of a degree | 
south of him. She will be at greatest eastern | 
elongation July 16, being at that time 45° 33' east | 
of tlie sun, and having a half-moon phase. She I 
will be 4° north of the moon July 22, at the time 1 
of setting. Venus is moving eastward past the , 
stars, passing from the eastern part of Cancer i 
to the eastern part of Leo in July. On the 5th | 
of July she will cross the handle of the Sickle j 
in Leo, being but one-half degree north of ' 
A Leonis (Eegulus). Venus sets as follows : 
July 5— 9h. 57m. evening. 
" 15— 9h. 38m. 
" 25— 9h. 16m. 
Mars will be 8° south of the Moon July 11» , 
