THE YOUNG SCIENTIST. 
25 
made largely of wood. There is not much 
room for choice amongst lathes of this 
kind. 
When the intending purchaser is not 
confined to the cheapest form of lathe, the 
first question that will arise is as to the 
size that should be procured. At first 
sight it would seem that the larger the 
better— within reasonable limits. For 
since small objects can be turned on a 
large lathe, while large objects cannot be 
turned on a small lathe, it would seem 
that all the advantage was on the side of 
the large lathe, and to get two, a large and a 
small, would be to imitate the man who had 
two holes made in his barn door— a large 
one for the old cat and a small one for the 
little kittens, forgetting that a very small 
kitten can go through a very large hole. 
A lathe that is too small is a constant 
source of annoyance where the owner de- 
sires to do general work. Of course if the 
lathe is intended for some special depart- 
ment, such as turning the fittings of small 
optical apparatus, such as microscope ob- 
jectives, etc., the case is different, but this 
is not a frequent case. 
There are two directions in which the 
size of a lathe is measured ; the first is the 
diameter of the object which it is capable 
of turning, and the other is the length of 
the article which it can take in. Some 
lathes are made capable of taking in work 
of very large diameter, while the beds 
being very short, they are fitted for turn- 
ing up wheels, pulleys, and such articles, 
but not for anything that is long. Other 
lathes are made exactly the reverse of this, 
being fitted for turning articles of great 
length but small diameter. The amateur, 
however, unless he has some special work 
in view, should select a well-proportioned 
lathe, and we think that one capable of 
taking in articles eight to nine inches in 
diameter, and three feet long, is about as 
good a size as can be chosen. When we 
say eight or nine inches in diameter, we 
mean, of course, over the bed, and not 
over the rest, for it will scarcely happen 
that the amateur will have to turn an ob- 
ject nine inches in diameter and three feet 
long, though he may often have to turn 
objects three feet long, and others that 
are nine inches in diameter. 
I When articles of greater length or di- 
ameter are to be turned, it will often hap- 
pen that the young workman can, by a 
little contrivance, devise means for per- 
forming the work. Thus, in our own prac- 
tice, we have often managed to build up a 
temporary bed, on which the tail-stocli: 
might be placed, and in this way we have 
succeeded in turning up simple work of 
considerable length. And on the other 
hand, by turning the head-stock round so 
that the face-plate would hang over the 
left-hand end of the shears, and by rig- 
ging up a temporary support for the 
tool rest, we have succeeded in turning up 
articles of considerable diameter on a 
very moderate-sized lathe. 
Of course these make-shifts will not do 
for intricate work, or for turning metal or 
heavy pieces of hard wood, but they answer 
very w^ell for light and simple objects. 
Having decided upon the size and price, 
the next thing to be done is to examine 
the various lathes in market, so as to 
select the best that comes within the 
limits of the points we have mentioned. 
Each part of the lathe under inspection 
should be carefully examined, and direc- 
tions for doing this will be given in our 
next article. 
BOOK NOTICES. 
Practical Hints on the Selection and TTse 
of the Microscope: Intended for the Use 
of Beginners. By John Phin, Editor of the 
American Journal of Microscopy and the Young 
Scientist. Third Edition. Thoroughly Reyised 
and Greatly Enlarged. With Six Full Page 
Plates and Seventy-six Figures in the Text. 
Price 75 cents. New York: Industrial Publica- 
tion Co. 
This work has been out of print for some time, 
as the publishers were unwilling to send the old 
plates to press without thorough correction. The 
work of reyision has been more extensile than 
was anticipated, and has occupied considerable 
time, but the adyance sheets of the work are now 
on our desk, and the complete yolume will be ac- 
cessible to our readers before many days pass by. 
The book we leave toother hands for criticism. 
That it has numerous faults we are fully aware, 
and we know that these haye not been entirely 
eliminated. Fully one half the book has, how- 
ever, been entirely rewritten, and the whole has 
been extended to 240 pages, instead of the 181 of 
the former edition. The kind reception accorded 
to the first and second editions leads the author 
to hope that the present one will not be entirely- 
unacceptable to our young friends who are inter- 
ested in microscopy. 
