370 Analyses of Books [Nov. 
tain extent, though his eloquence, in spite of his origin, be not 
indeed of the purest Tuscan. I had almost forgotten to state, 
that Venoceio Biringuccio. was a native of Sienna. 
Lam, dear Sir, yours truly, 
J.J. CONYBEARE. 
ArTICLE XII. 
ANALYSES oF Booxs. 
Philosophical Transactions of the Royal Society of London, for 
1822. Part I. 
We have to apologize for so long delaying to analyze this part, 
which contains a series of papers of great importance; two of 
the most interesting, however, have already been inserted at 
length in the three preceding numbers of the Annals. 
I. The Bakerian Lecture.x—An Account of Experiments to 
determine the Amount of the Dip of the Magnetic Needle in Lon- 
don, in August 1821; with Remarks on the Instruments which are 
usually employed in such Determinations. _By Capt. Edward 
Sabine, of the Royal Regiment of Artillery, PRS. 
Capt. Sabine remarks, that the increased attention which has 
been given of late years to the subject of magnetism, and the 
consequent advance that has been made in the science, render 
it desirable that a greater degree of accuracy should be obtained, 
in the observation of its terrestrial phenomena, than has hitherto 
been the case. The instruments for ascertaining the dip of the 
needle, it is stated, have received little or no improvement dur- 
ing the last 50 years, and produce results, which, with every 
precaution, can be considered as approximate only. 
After describing the imperfections in the instruments alluded 
to, and explaining the errors which originate in them, the author 
proceeds to give an account of a dipping-needle, which he 
requested Mr. Dollond to make, on a construction suggested by 
Prof. Meyer, of Gottingen ; as well as of the mode of observa- 
tion therewith. ‘The needle is a parallelopipedon of eleven 
inches and a half in length, four-tenths in breadth, and one- 
twentieth in thickness ; the ends are rounded ; and a line marked 
on the face of the needle passing through the centre to the 
extremities, answers the purpose of an index. The cylindrical 
axis on which the needle revolves, is of bell metal, terminated, 
where it rests on the agate planes, by cylinders of less diameter ; 
the finer these terminations are made, so long as they do not 
bend with the weight of the needle, the more accurate will be 
the oscillations ; small grooves in the thicker part of the axis 
