436 New Pullications. 
Mr. Sowerby has announced to his friends that, as soom 
as English Botany (an arduous work of more than twenty 
years) and British Mineralogy are finished, he will com- 
mence a work to be written by Dr. Leach of the British 
Museum, upon the Malacostraca Britannica or British Crabs. 
He supposes the first number will appear soon alter March, 
before which time English Botany cannot be finished on 
account of the difficulty of procuring the few mosses yet 
unpublished. 
The British Mineralogy being nearly completed, it would 
be doing the public a great service if mineralogists would 
send Mr. Sowerby, for the purpose of figuring, such newly 
discovered minerals as may not already have appeared in 
that work. Mr. S. will also feel sincerely grateful to his 
friends for any remarks they may wish to make, or any in- 
accuracies they may point out depending on the rapid im- 
provement in mineralogical knowledge, made during the pro~ 
gress of this work. Localities of fossil shells for his Mineral 
Conchology will also be thankfully received. 
2, Mead Place, Lambeth. 
A very useful work has just made its appearance entitled, 
A practical Treatise on Mill-work and other Machinery, in 
seven Parts. By Robertson Buchanan +, Civil Engineer. 
1. On the teeth of wheels and of wheel-work. 
2. On the shafts of mills. 
3. On the longitudinal connexions of shafts denominated 
couplings. . 
4 On the methods of disengaging and reengaging machi~ 
nery while in motion. 
5. On mechanisin for equalizing the motion of mills. 
_ 6. On changing the velocity of machinery while in mo- 
tion. 
7. On the framing of mill-work. 
The Rev. John Toplis, B.D. Fellow of Queen’s College, 
Cambridge, has in the press, a Translation of the Treatise 
upon Mechanics, which forms the introduction to the M/é= 
chanique Céleste of P.S. Laplace. It will be accompanied 
by copious explanatory notes and additions, which are in- 
tended, im some degree, to obviate those difficulties in the 
Méchanique Célesie, the Méchanique Analytique, &c. of 
which many readers, who have not been conversant with 
the works of foreign mathematicians, complain. 
_¢ Author of a Treatise on Fyel and the Heating of Buildings by Steal 
. 
LECTURES. 
