THE YOUNG SCIENTIST. 
15 
filing out. However, it is better to avoid doing 
it than to have to eradicate it after it is done. 
When the work has been well finished with the 
stick and oilstone powder, a clean huf£, with a 
little rottenstone and oil, and then dry rotten- 
stone should be used, and, if properly done, a 
most beautiful, bright, clean, and fiat finish is 
obtained. Having finished the edges thus, to do 
the surfaces will be the next part. They, also, 
must have all the marks of the file taken out, 
and be got quite smooth from the paper. This 
done, if it is to be curled, which is the best and 
most ornamental way of finishing such work 
nowadays, a piece of water-of-ayr stone, used 
with water, will remove such scratches as may 
be left from the emery-paper ; also, it produces 
a kind of cloud, previous to using the charcoal, 
which is the next process. Take a piece of cut- 
ting charcoal, which, by the way, there is some 
difficulty in obtaining, and it can only be got by 
going to some coal shed which, as a rule, is not 
of the most inviting; but if a thing is really 
wanted it must be obtained, even at the risk of 
having to attend one of these disagreeable habi- 
tations ; and as I am telling our readers of the 
means of getting what they require, I may as 
well tell where the place is. In Crown Court, I 
think it is, in Newport Market, this material is 
to be found, and as there are several kinds, it 
is better to take a piece of brass and try it before 
purchasing, as some will cut, some will not, and 
out of fifty pieces perhaps only two or three will 
be of any use. Noav having, we will assume, 
procured the material, unless it is properly used 
we may as well be without it. Before trying, I 
file one end fiat, and liaving a small basin of j 
water by your side, dip tiie charcoal into it, and j 
by curling it round and round in all directions j 
the clouded surface is formed. Now, it must! 
not be thought that by simply doing this that a | 
good result will be obtained, for it is, in reality, 
a difficult thing to do, and unless well done it 
looks very inferior, and would be better left 
alone. When the surface is finished with this 
process, the next thing to be used is a piece of 
slate pencil brought to a point. This is also 
used with water, to make it cut, and is made to 
produce a series of small circles or rings, which 
must not be done with any regularity, but in- 
discriminately in all directions. There is great 
knack in all these different styles of finishing 
work, and there are not two men that do this 
particular branch in the same manner. This 
done, the next thing will be to lacquer it. This 
is similar to varnishing wood, the difference 
being that the metal must be made hot. I do 
not mean red hot, but after it has been well 
wiped over and brushed out with whiting, to 
ta^e all the grease out, it should be put on a 
piece of red hot iron, and remain there till it is 
so hot that your finger would be quickly with- 
drawn if placed upon it. When it is taken off 
the iron, well wipe it again with a clean, dry rag, 
because where there is any grease the lacquer 
will not take, and on those parts it will show a 
dirty discolored mark in a short time. Always 
lacquer the edges of your w^ork first. In using 
the brush a very light hand is necessary, and 
no more lacquer let in the brush than you can 
help. Above all things, both lacquer, brush, 
pot, and work must be free from dirt and dust. 
By following out these directions the superior 
finish seen on the best work may, be obtained, 
and after all there is really little difficulty in it ;. 
care is one of the most essential points, and 
without that good work of any kind cannot be 
done.— i^orgre and Lathe. 
Good Joints. 
Our young friends who exercise their ingenu- 
ity in the construction of useful articles, and es- 
pecially in making repairs about the homestead 
should give particular attention to the forma- 
tion of the joints by which the different parts 
are united. One of the highest authorities, the 
late Professor Kankine sums up the principles 
which should be adhered to in designing joints 
and fastenings in carpentry, concisely as io! 
lows : First, to cut the joints and arrange tli 
fastenings so as to w^eaken the pieces of timber 
they connect as little as possible. Second, to 
place each abutting surface in joint as nearly as 
possible perpendicular to the pressure which it; 
has to transmit. Third, to proportion the area 
of each surface to the pressure which it has to 
bear, so that the timber may be safe against in- 
jury under the heaviest load that occurs in prac- 
tice ; and to form and fit every pair of such sur- 
faces accurately, in order to distribute the stress 
uniformly. Four, to proportion the fastenings 
so that they may be of equal strength with the 
pieces which they connect. Five, to place the 
fastenings in each piece of timber so that there, 
shall be sufficient resistance to the giving way 
of the joint by the fastenings shearing or crush- 
ing their way through the timber. 
Liquid India Ink.— When India ink is Icept in 
a llQuid state it soon becomes worthless, from the 
facttliat the gelatine which it contains decom- 
poses. A little glycerine added acts as a preserva- 
tive, and causes the ink to flow well. Too much 
glycerine will prevent the ink from drying, and 
in this case it is, of course, easily blotched or 
smeared. 
