680 
simple form possible to his reasonings, 
and on this occasion he considers the 
orbit of each pianet as an ellipsis, vari- 
able every. instant. These are repre- 
sented, 
whe By the demi- -great axis, on which 
depends the medium motion of the 
planet. 
2. By the epoch of the medium lon- 
gitude. 
3. By the eccentricity of the orbit. 
4. By the longitude of the perihelion. 
5. By the inclination of the orbit, 
And, 6. By the longitude of its parts. 
ss VE. Lagrange,” adds he * has long 
since given to the differential expression 
of the great axis the form of which-I 
have just spoken; and he has concluded 
with great propriety from thence, the in- 
variability of the proportional motions, 
when regard is only paid to the first 
power of the perturbatory masses. This, 
I myself was the first to reeoguise, by 
only, rejecting one-fourth of the power of: 
the eccentricities sand inclinations; a 
calcuiation which proved sufficient for 
all the purposes of astronomy. Accord- 
ingly, in the second book of the “ Mé- 
canique Celeste,” I have given the same 
form to the differential expressions- of 
the eccentricity of the orbit, ws inclina- 
. tion, and the longitude of its parts. It 
remained therefore only to give the same 
form to the diiferential expressions- of 
the longitudes of the epoch and the 
perihelion, which I have done in this 
place.” 
“ Memoires de Chimie,- auten aut 
des Analyses de Mineraur, &c.”—Me- 
moirs ohChemistry, containing Analyses 
of Minerals, by Martin Henry Kuap- 
roTH, Professor of Chemistry at the 
Academy for the Artillery in *Prassia, 
an Associate of the National Institute of 
France. &c. 2 vois.-8vo. printed at 
Paris, and imported by M. de Botte, 
Nassau-street. 
The author tells us in his preface, 
which is here translated at. full length, 
that he has long Hand aap the project 
of collecting all the different memoirs on 
chemistry hitherto written by him, but 
never found time for this ee Pie . 
“Tn presenting to the public,” 
Minerals, containing tsventy-six disser- 
tations, the greater part of which now 
appear for the first time, I have engica- 
voured to render my labours as complete 
as possible ; but I have experienced how 
dificult, and even how impossible i it was, 
‘to render analyses perfect. IF have at- 
tempted, not only to analyze Species, 
says” 
he, “ this first volume of the Analyses of _ 
Retrospect of French Literature—Miscellanies. 
but even genera; yet I soon perceived 
that this task was too great for a single 
individual, and. was accordingly turced 
to abandon i It. 
“ As T most ardently desire to behold 
the scienee taking a wider range, i COn= 
sequence of regular and correct expe- 
riments, [ am of course anxious that the 
wish of Bergmann may be accomplished = 
“ Alioruam tentamina, presertim cardi- 
nalia, candide sunt revidenda.” For as: 
this chemical philosopher very properly 
observes: ‘plus vident oceuli, quans | 
oculus; ideoque, que nova exhibentur 
pluribus, testibus in diversis locis utiliter — 
confirmari puto.” 
The author thinks that his analytical : 
method in respect to gems merits atteh- 
tion, and even imitation, from the ablest 
Much is said to depend on 
Platina’ 
chemists. 
the choice of proper vessels. 
itself does not resist the continual action 
of pot-ash in fusion; he himself usually 
makes use of a silver vase for experi- 
ments, and he recommends a golden 
one! 
na Sammlung Astronomischer Abhand= - 
langen, &c.”—A Collection of Memoirs, 
Observations, and Astronomical Notices, 
by J. L. Bove, 4 vols. 8vo. with hee 
Berlin, 1809. 
This astronomer, who is. well Laswell 
throughout Germany, has in this work 
collected a great variety of memviss on 
different branches of that science which 
he professes. 
only select a few: 
1. Tabies of the Moon, according to 
the longitudinal equations of Burg, and = 
also those of the latitudes and parallaxes 
of Laplace, by Oltmans. | 
2. Of the direction of the sun’s move= 
ment, and the solar system,-by Hers- 
chel. 
Of these we shall here _ 
3. Geographical position of Porto 
Rigas by Olemans. 
4. Geographical positions, and astro= 
nomical observations, made in Sweden 
during the years 1801-2-3 and 4. 
5. Formule of the precession, by 
Pfatts.. 
6. On the problem, to find the true 
position of a planet by means of the — 
medium of its longitude, by Rohde. 
7. Geographical position of the city 
of Pilsen, in Bohemia, by David. 
8. On the influence of reciprocal at- 
_traction of three bodies on the move- 
ment of one of these bodies, by Hegner.- 
9. Trigometrical measurement of the — 
duchy of Berg, by Benzenberg. 
10. Geographical longitude of Lan- 
caster, in Pennsylvania, by Oltmans. | 
11.. Method 
/ 
"ao 
ae 
