THE YOUNG SCIENTIST. 
31 
for a few minutes under a negative or drawing, 
and developed with a solution of one part ferro- 
cyanide of potassium in 5 parts of water applied 
with a brush. It is fixed with dilute hydrochloric 
acid, 1 to 10, washed thoroughly and dried — 
Boston Journal of Chemistry. 
Sulphur as a Lubricator.— This substance 
has been long known as a moet excellent anti- 
friction agent, and it has of late been very suc- 
cessfully used by the steamers of the North 
German Lloyds. The sulphur is mixed with oil 
or grease and applied like any ordinary lubri- 
cator. It combines with the fine metal dust worn 
off by friction and entirely prevents heating. 
Liquid Grlue.— The Muster Zeitung recom- 
mends, in preference to the treatment of glue 
with nitric acid, the following: So-called gela- 
tine is dissolved in the water-bath in its own 
weight of strong vinegar, a quarter part of 
alcohol, and a very little alum. This glue re- 
mains liquid when cold, and is much used for 
cementing mother of pearl, horn, etc., upon wood 
or metal. 
Treatment of New Files.— A new file should 
be used with a light pressure until the very thin 
sharp edges are worn off, after which a heavier 
pressure may be used with much less danger of 
the teeth crumbling at the top or breaking off at 
the base. Every filer should keep a partially worn 
file to use first on chilled surfaces or gritty skin 
of castings, or on a weld where borax or similar 
fluxes have been employed, or on the glazed sur- 
face of saws after gumming. 
Stove Polish.— The fine polish given stoves 
by those skilled in the art, is produced as follows ; 
Have a thin mixture of black varnish and turpen- 
tine ; apply this with a paint or varnish brush to 
a portion of the stove ; then with a cloth dust this 
over with pulverized British lustre or stove 
polish: then rub with a dry brush. The stove 
must be perfectly cold. The stove dealers buy 
the pulverized stove polish, which is carburet of 
iron, in 25-lb. packages. The process conducted 
in this manner is quite brief, but gives beautiful 
results. 
Plate Polishing- Paste.— The English Me- 
chanic states that an excellent preparation for 
polishing plate may be made in the following 
manner: Mix together 4 ounces spirits of tur- 
pentine, 2 ounces spirits of wine, l ounce spirits 
of camphor, and K ounce spirits of ammonia. To 
this addione pound of whiting, finely powdered, 
and stir till the whole is of the consistency of thick 
cream. To use this preparation, with a clean 
sponge cover the silver with it, so as to give it a 
coat like whitewash. Set the silver aside till the 
paste has dried into a powder ; then brush it off, 
and polish with a chamois leather. A cheaper 
kind may be made by merely mixing spirits of 
wine and whiting together. 
To Bleach Straw.— Dissolve 108 grains (about 
4 ounces) permanganate of potash (crystals) in 5 
liters (or quarts) of hot water. Mix this solution 
in a tub of water until the water is a deep red. 
Enter straw which has previously been softened 
for several hours in a tepid bath of soda and well 
rinsed. Agitate the straw frequently. It will 
turn deep brown ; if not, add some permanganate 
solution ; leave it in till discoloration of the bath. 
When the straw is of a drab shade, rinse in cold 
water and enter in a bath of sulphurous acid. 
Make it of a sufficient degree to give forth odor. 
The discoloration of the straw takes place 
within 30 minutes, and generally turns a good 
white. 
Ocean Wave Power.— The Swales Ocean 
Wave Power Company has incorporated, to fur- 
nish power by means of the action of ocean waves 
and tides with which to supply salt water for 
watering streets, flushing sewers, supplying pub- 
lic and private baths, extinguishing fires, and 
other public and private purposes; for driving 
machinery, compressing air, generating electric- 
ity, and for all manufacturing and commercial 
purposes. 
||||^ Great Telescope.— The observatory in the 
neighborhood of Nice, which is being erected at 
the expense of M. Bischoffsheim, is rapidly ap- 
proaching completion. The great equatorial 
telescope is to be one of the largest in the world— 
perhaps the largest— as it will have an object 
glass three feet in diameter and a focal length of 
upwards of fifty feet. The construction of this 
monster telescope has been intrusted to MM, 
Paul and Prosper Henry, of Paris, and the total 
cost of the observatory will be more than $400,000 
in American money. 
Spiders Obstructing the Telegraph.— One 
of the chief hindrances to telegraphing in Japan 
is the grounding of the current by spider lines. 
The trees bordering the highways swarm with 
spiders, which spin their webs everywhere be- 
tween the earth, wires, posts, insulators, and 
trees. When the spider webs are covered with 
heavy dews they become good conductors and 
run the messages to earth. The only way to re- 
move the difficulty is by employing men to sweep 
the wires with brushes of bamboo, but as the 
spiders are more numerous and persistent than 
the brush users, the difficulty remains always a 
a serious one. 
The Light of the Stars.— For a number of 
years the special work carried on at the Hai-vard 
observatory, under the direction of Prof. Picker- 
ing, has been the measurement of the intensity 
of the light of the heavenly bodies. Some of the 
results presented at a recent meeting of the So- 
ciety of Arts, at the Institute of Technology, Bos- 
ton, indicate measurements almost incredibly 
fine. The light which falls upon the earth from 
the satellites of Mars, for example, is about 
equivalent to what a man's hand on which the 
