1823. ] tastitute 
Of these new. observations isnot a little 
owing to, the; ipstrnme nts iof) Messrsy 
Breguets ine fenten 
The ‘Lables of: Sapiter, Saturn, and 
Uranus, by, M- Bouvard; of the: Royal 
Observatory of Paris, are of recent date; 
and require, at least, honourable men- 
tion. In, the year 1822, four! comets 
appeared, the: first of which was disco- 
vered, by, M.,Gambard, at! Marseilles, 
and two others by M. Pons. 
of these, there have been only two! ob- 
servations, so jthat the elements of its 
orbit haye not been calenlated. | These 
elements have been ascertained for the 
other;two vomets.; ‘Lhey differ consi- 
derably from those that appertain to the 
precedisg .comets.'.. Hence’ we may 
judge that these are new. stars, or, at 
least, different from all those that have 
been hitherto observed. It is not the 
same. with the fourth comet observed in 
1822; it, is,; evidently, that of 1783, 
1795,,1805; and) 1819. | Its revolution 
about the sun takes up 1202 days. The 
return of this star is an astronomical 
event of great jinterest.. From its pau- 
city, of Justre, and. erepuscular light, it 
was not visible in Europe, nor discerni- 
ble at the Observatory of the Cape of 
Good; Hope; but it has recently been 
discoyered.in.a region the. most distant 
from, Europe, in New Holland: The 
astronomers of Ahe Observatory of Para- 
matta, the latest establisument of this 
kind, discovercd this comet in the 
month of Jutie, 1822, and in positions 
very, near to, those that had: been before 
calculated. . ‘Lhe foundation of this new 
Observatory may be ascribed to General 
Brisbane,,Governor, of ‘New South 
Wales, and a very. intelligent corres- 
pondent of the Academy of Sciences. 
The comet of 1759, observed by 
Halicy and. Clairaut, was hitherto the 
only star whose elliptical revolntion was 
known ,and..positively determined ; the 
period, of itsrettirn is about seventy 
years. . The comet spoken of a little 
above;,has been calculated, as to» its 
elliptical, elements, by» M. Euke, and 
possesses this peculiar advantage, that 
it will become visible ten times. ain) 
thirty-three years. | The lengthened 
ellipsis which, it; describes, is included 
within the Jimits.of our. solar system. 
Its least distance from the sun is about 
three timesess than that of the earth, 
and its, greatest distance is eqnal | to 
twelve times the, least, 
This, comet, perhaps; may help, us to 
agquire some fresh information respect- 
ing the sivgular;natare of these stars, 
For one’ 
of France. AAS 
which? appear’ to bave very little of a 
solid »mass'“or? body,’ aad’ to’ Consist 
chiefly of, condensed Yapours?’ Liv otir 
planetary ‘system; théy donot sive Hse 
to: any ‘sensible’ perturbation, Dat! they 
themselves undeygo'very” considerable’ 
ones. “Their course'cannoft be’ duly 
fixed, if the mass gradually chanees, or 
separates, or dissipates; so long, ‘how- 
ever, as the mass subsists, ‘these’ stars 
are subject to the known laws of gravity 5 
so that there is none of them whose ob- 
servation does not eall forth fresh’ proofs 
of the verity of the principles of mudern 
astronomy. 
Among other applications of ‘mecha 
nical ‘theories, we ‘should not omit to 
notice an ingenious process of M. de 
Prony, which serves to measure’ the 
dynamic effect of rotatory machines}'as 
also the Memoir of M. Girard; on ‘the 
Resisting Power of Cylindrical Enve¥ 
lopes or Covers; and a remarkable work, 
just published, of the same authior, 
treating of Hydraulics, the Course’ of 
Rivers, and the Regimen to which they 
might be subjected, and’ of Commerce’ 
and Industry generally. 
A number of mechanical or physivar 
Questions, that enter into the concerns of 
civil life, have been addressed to the 
academy by the government.) The first 
relates to the public use of earriages, to 
prevent accidents that may arise from'a 
want of stability, or frou a detective 
construction, or from an improper’ dis- 
tribution of the luggage, or from exces.) 
sive speed when iu motion, or friém the 
constraction of the reads. ° The bther! 
Questions relate to lightauing-colductors, 
lo the areometrical process ‘requisite te 
measure, with precision, the -specifie 
weight of liquids; also to the ase of ma- 
chines moved by, the foree of steam)and 
the methods most. proper: to chs 
against their fatal explosions, 
“These. G vuestions have undergone ex+ 
amination by Select Commiitees,o°M: 
Arago drew upithe Reportion Arcomes 
ters; M.: Gay-Lussac that on'tlie Con’ 
struction of Paratonnerres, (Lightning ’ 
Conductors 3) andoMy Dapin," thice 
Reports on the Stabilityoof Carriages in 
Roads, on the: use ofoSteam Bovines; 
and on the asc of Pire Rngines, * He is 
proceeding in the» publication’ of his 
Mathematical Memoirsy:and his work’ 
detailing: the Nautical,’ Military, ‘and 
Commercial Establishments ‘of Gieat 
Britaia.yltoiotp loos MANY 
‘From this brief expoxittons it’ appears 
evident, that theories cannot make'la y 
considerable progress without numer 
: action 
