94 
THE YOUNG 8CIENTI8T. 
purpose of pufBng some patent ; it is short, 
simple, and fully illustrated, and the practical 
directions are so full, that any ordinary mechanic 
•can, by following them, put up a really good rod. 
And it is a comforting assurance to be told that 
a really good rod need not infringe any patent, 
-the best methods of construction being older than 
a.ny patents no^y in force. 
The New York Evening- Express Almanac 
for 1879: Handbook of Politics, Statesman's 
Manual and Statistical Register for Bankers, 
Merchants and Agriculturists. Price 25 cents. 
New York: Oflfice of Evening Express. 
The range of subjects which the compilers of 
this almanac have compressed into its pages is 
something astonishing. We have here a goodly 
volume of nearly 400 large octavo pages filled with 
Important statistics and general information. In 
addition to the usual matter found in all alma- 
nacs, it contains an enormous amount of general 
information in regard to the products, commerce, 
politics, geography, education, etc., of almost 
•every country in the world, and all so arranged 
and condensed as to be easily available at a 
moment's notice. How all this can be done for 
25 cents is one of the marvels of bookmaking. 
Green Varnish. 
There is a most beautiful transparent green 
varnish employed to give a fine glittering color 
to gilt or other decorated works. As the prepar- 
ation of this varnish is very little known, an 
account of it may in all probability prove of 
interest to many of our readers. The process is 
as follows :— Grind a small quantity of a pecu- 
liar pigment, called " Chinese blue," along with 
£ibout double the quantity of finely-powdered 
ehromate of potash, and a sufficient quantity of 
•copal varnish thinned with turpentine. The 
mixture requires the most elaborate grinding or 
incorporating of its ingredients, otherwise it 
•will not be transparent, and therefore useless 
for the purpose for which it is intended. The 
^' tone " of the color may be varied by an altera- 
tion in the proportion of the ingredients :— A 
preponderance of ehromate of potash causes a 
y ellowish shade in the green, as might have 
been expected, and vice versa with the blue un- 
der the same circumstances. This colored var- 
nish will produce a very striking effect in jap- 
aiined goods, paper-hangings, &c., and can be 
made at a very cheap rate.— Cabinet-ma'ker. 
Nickel Plating^. 
A foreign exchange gives the following re- 
cipe : To a solution of five to ten per cent, of 
chl©ifde of zinc, as pure as possible, add suf- 
ficient sulphate of nickel to produce a strong 
green color, and bring to boiling in a porcelain 
vessel. The piece to be plated, which must be 
perfectly bright and free from grease, is intro-- 
duced so that it touches the vessel as little as 
possible. Ebullition is continued from 30 to. 
60 minutes, water being added from time to 
time to replace that evaporated. During ebul- 
lition nickel is precipitated in the form of a 
white and brilliant coating. The boiling can be 
continued for hours without sensibly increasing 
the thickness of this coating. As soon as the 
object appears to be plated it is washed in water 
containing a little chalk in suspension, and then 
carefully dried. This coating may be scoured 
with chalk, and is very adherent. The chloride 
of zinc and also the sulphate of nickel used 
must be free from metals precipitable by iron. 
If during the precipitation the liquor becomes 
colorless, sulphate of nickel should be added. 
The spent liquor may be used again by exposing 
to the air until the contained iron is precipitated, 
filtering and adding the zinc and nickel salts 
above. Cobalt also may be deposited in the 
same manner. 
. • ♦ • 
Plaster of Paris. 
Plaster of Paris may be made to set very 
quickly by mixing in warm water to which a 
little sulphate of potassium has been added. 
Plaster of Paris casts, soaked in melted paraffin, 
may be readily cut or turned in a lathe. They 
may be rendered very hard and tough by soak- 
ing them in glue-size until thoroughly satu- 
rated, and allowing them to dry. Casts of plaster 
of Paris may be made to imitate fine bronze by 
giving them two or three coats of shellac var- 
nish, and when dry applying a coat of mastic 
varnish, and dusting on fine bronze powder 
when the mastic varnish becomes sticky. Kat- 
holes may be effectually stopped with broken 
glass and plaster of Paris. The best method of 
mixing plaster of Paris is to sprinkle it into 
water, using rather more water than is required 
for the batter ; when the plaster settles pour oiT 
the surplus water, and stir carefully. Air bub- 
bles are avoided in this way.— Scientific Ameri- 
can. 
Splitting Paper. 
It is one of the most remarkable properties of 
that wonderful product, paper, that it can be 
split into two or even three parts, however thin 
the sheet. We have seen a leaf of the Illustrated 
News thus divided into three parts, or three thin 
leaves. One consisted of the surface on which 
the engravings are printed; another was the 
side containing the letter press, and a perfectly 
blank piece on each side was the paper that lay 
l^etween. Many people who have not seen this 
done might think it impossible ; yet it is not 
