THE YOUNG SCIENTIST. 
only possible, but extremely easy, as we shall 
show. 
Get a piece of plate glass and place on it a 
sheet of paper ; then let the latter be thoroughly 
soaked. With care and a little dexterity the 
sheet can be split by the top surface being re- 
moved. But the best plan is to paste a piece of 
cloth or strong paper to each side of the sheet 
to be split. When dry, violently and without 
hesitation pull the two pieces asunder, when 
part of the sheet will be found to have adhered 
to one and part to the other. Soften the paste 
in water and the pieces can bo easily removed 
from the cloth. 
The process is generally demonstrated as a 
matter of curiosity, yet it can be utilized in 
various ways. If we want to paste in a scrap- 
book a newspaper article printed on both sides 
of the paper, and possess only one copy, it is 
very convenient to know how to detach the one 
side from the other. The paper when split, as 
may be imagined, is more transparent than it 
was before being subjected to the operation, and 
the printing ink is somewhat duller ; otherwise 
the two pieces present the appearance of the 
original if again brought together. 
Some time ago the information of how to do 
this splitting was advertised to be sold for a 
•considerable sum. We now impart it to all our 
readers gratuitously. — B. and 0. Printer and 
Stciioner. 
Cleaning- Brass.— Finely rubbed bichromate 
of potash mixed with twice its bulk of sulphuric 
acid and an equal ctuantity of water, will clean the 
dirtiest brass very quickly. 
Marine G-lue.— The following recipe is said 
to give very good results : Dissolve one part of 
India-rubber in 12 parts of benzole, and to the 
solution add 20 parts of powdered shellac, heating 
the mixture oa'.t^iO(isZy over the fire. Apply with 
' a brush. This is much used in the construction 
of galvanic batteries. 
To Restore Spotted Varnish.— If the varnish 
has been blistered by heat or corroded by strong 
acids, the only remedy is to scrape or sandpaper 
the article and revarnish. Spots may often be re- 
moved by the following process: Make a mixture 
of equal parts of linseed-oil, alcohol, and turpen- 
tine, slightly moisten a rag with it, and rub the 
, spots until they disappear. Then polish the spot 
I with ordinary blotting paper. Varnish injured 
i by heat can hardly be restored in any other way 
than by removing it and applying v. fresh coat. 
To Make Iron Take a Bright Polish Like 
i Steel,— PulTerize and dissolve the following arti- 
I cles in one quart of hot water: Blue vitriol, one 
ounce; borax, one ounce; prussiate of potash, 
one ounce ; charcoal, one ounce ; salt, one half- 
pint ; then add one gallon linseed oil. Mix well, 
bring your iron or steel to the proper heat and 
cool in the solution. It is said the manufacturers 
of a certain governor paid $100 for this recipe, 
the object being to case-harden iron so that it 
would take a bright polish like steel. We regard 
the process as one of questionable utility. 
Cements.— To make cement for attaching 
labels to metals, take ten parts tragacanth mucli- 
age, ten parts of honey, and one part flour. Tho 
flour appears to hasten the drying, and renders 
it less susceptible to damp. Another cement that 
will resist the damp still better, but will not ad- 
here if the surface is greasy, is made by boiling 
together two parts shellac, one part borax, and 
sixteen parts water. Flour paste to which a cer- 
tain proportion of nitric acid has been added, and 
heat api)lied, makes a lasting cement, but the 
acid often acts upon the metals. The acid con- 
verts the starch into dextrine. 
Potassium.— The metallic appearance of potas- 
sium is usually exhibited by cutting a fresh sur- 
face which is immediately examined. But the 
surface becomes dim almost instantly. As a lec- 
ture experiment, Dr. Erckmann, introduces a 
piece of potassium, of the size of a pea, into a 
small test tube, heats to fusion, turns the glass 
round and round till the metal congeals, and then 
seals up the tube. The greater part of the potas- 
sium is deposited on the sides of tho tube as a 
specular metallic coating, resembling silver, and 
can be exhibited during lectures, etc. The other 
alkaline metals may be similarly treated. 
To Protect Iron from Rust.— Iron can be 
protected from rust and made very pleasing in 
color by a method invented by Mr. Dode. He coats 
the surface with a thin film of borate of lead, in 
which some oxide of copper has been dissolved, 
and some scales of precipitated platinum held in 
suspension, by means of a brush or a bath. He 
then heats the composition until it is dilTused. 
The result is a thin, glassy coating, which will 
withstand the action of sewer gases, dilute acids 
or alkalies, and the heat of a kitchen fire. If all 
be true that is said of this " platinized iron," as it 
j is called, it will And numerous applications. — 
Kansas City Rev. of Sci. and Lid. 
Glue.— Carpenters should remembor that fresh 
glue dries more readily than that which has been 
once or twice melted. Dry glue steeped in cold 
water absorbs different quantities of water accord- 
ing to the quality of the glue, while the propor- 
tion of the water so absorbed may be used as a 
test of the quality of the glue. From careful ex- 
periments with dry glue immersed for twenty- 
four hours in water at 60'^ Fah., and thereby trans- 
formed into a jelly, it was found that the finest 
ordinary glue, or that made from white bones, 
absorbs twelve times its weight of water in 
twenty-four hours; from dark bones, the glue 
absorbs nine times its weight of water; while the 
ordinary glue, made from animal refuse, absorbs 
but three to five times its weight of y^-Ai^v. —Build- 
ing News, 
