THE YOUNG SCIENTIST. 
139 
evenly on a board, and used dry, will re- 
new the surface of an ordinary oil-stone. 
Or I block of sand-stone, which has been 
dressed straight, will do. The following 
plan has been highly recommended by a 
correspondent of the Scientific American. 
He says: "1 have, in the course of my 
life, spent a good deal of time in facing 
off my oil-stones. I have used sand on a 
board, wet and dry, or an old millstone, 
or a hard brick. If the oil-stone was soft, 
it could be cut or rubbed down in a short 
time ; but if a hard one, it was a serious 
job. The thought struck me, about two 
years ago, that emery would be the thing 
to quickly cut a hard stone wdiich 1 have. 
I dressed off a wdiite pine board, put a 
thin coat of glue on it, when dry put on 
another, sprinkled coarse emery on the 
glue, rubbed it in well, and when dry put 
on another coat of glue and emery. I 
have been using it ever since ; it does not 
take one-tenth of the time to face off that 
stone that it formerly did with sand, etc. 
This may save some one some hard 
rubbing. ' ' 
When a stone has once been brought 
into good condition, try to keep it so. 
Never use it without a liberal supply of 
good oil, which must be of some non- 
drying kind, if you would keep the stone 
in order. Olive oil or sperm oil is what 
we use. We have tried soap, glycerine, 
kerosene, etc., etc., but find that although 
they work well for a few minutes, they 
soon spoil the stone. As soon as you 
have finished your work, wipe the stone 
off clean, and cover it up to keep it from 
the air. The best way is to keep it in a 
wooden case, carefully fitted to it, but 
when the stone has no case, wrap it care- 
fully in several folds of paper. No stone 
will do good service unless the surface is 
kept even and straight; therefore avoid 
using the middle of the stone more than 
the ends, and as soon as any part gets 
worn below the general level, have the 
whole surface dressed off even. 
Our January Number. 
THIS will contain several finely illus- 
trated and interesting articles, in 
eluding a handsome frontispiece, which 
illustrates a very singular experiment. 
The article on Pond Life will be con- 
tinued, and there will be articles of great 
practical value on the Aquarium, the 
Turning Lathe, Makeshifts for Young 
Microscopists, etc., etc. The first of a 
series of three articles on Cutting and 
Engraving Glass. This series will include 
a very simple arrangement for the sand- 
blast. Our young friends should be 
careful not to miss this number. 
—Iridium is the least fusible of all 
metals, requiring a temperature of about 
3500° Fahr. Platinum, melts at about 
3200° Fahr. 
A Word to Our Subscribers. 
THE present year is drawing to a close, 
there being but one more number to 
be sent to each subscriber. That number 
will contain index and title page, so that 
those who wish to have their journals 
bound can have a complete book. 
For the coming year we have made 
such arrangements as we believe will ena- 
ble us to give our readers better satisfac- 
tion than ever before. It is our purpose 
to steadily improve the Young Scientist, 
and we intend that every number shall be 
better than those tliat have preceded it. 
That we may be able to do this, however, 
we must secure the help of our subscri- 
bers. We ought to have a subscription 
list double what we*now have— at least 
fifteen thousand — and we can easily do 
this if our friends will only help us. Let 
each one of our subscribers send in a new 
name and the thing is done. But remem- 
ber we do not ask you to do this for noth- 
ing. We are willing to pay, and pay well, 
for this little service, and therefore we 
make the following liberal offer, which 
will hold good until the 25th of December, 
Christmas day. Those who wish to work 
for money, may retain fifteen cents out of 
the fifty received for every new name 
they send us. Those who wish books, can 
have twenty-five cents worth of any of 
o?(r own publications for every fifty cents 
that they remit for a new name. Thus 
