148 Analyses of Books. [Aue. 
Wianima: ig ateats aid oi dissed ad Be Be 
Brion.) ii its AES UERR  elg bitte: oth «Ohuace Ne 
Wrater un, sac st) enail uid. ad sie ed 
quantities that are not reconcileable to equivalent proportions. 
Yours truly, ? 
Joun GEORGE CHILDREN. 
ARTICLE IX. 
ANALYSES OF Books. 
Memoirs of the Astronomical Society of London. Vol. I. 
London. 1822. 
THOSE anticipations in which we ventured to indulge, when 
announcing the formation of the Astronomical Society, the con- 
tents of the present volume have fully justified. The list of its 
members comprehending names unquestionably the most distin- 
guished among the scientific, and the well-known zeal of many 
in the ptfactice of astronomy, gave assurance that numerous 
valuable communications would soon be presented to it. From 
the distinction which has been acquired by the artists of this 
country in the construction of astronomical instruments, it might 
naturally be expected that practical contributions of this descrip- 
tion would frequently appear; and accordingly among these 
memoirs, the first and second convey the results of the ingenious 
labours of Troughton and Dollond; the former giving “ an 
account of the repeating circle, and of the altitude and azimuth 
instrument ; describing their different constructions, the manner 
of performing their principal adjustments, and how to make 
observations with them, together with a comparison of their 
respective advantages ;” and the latter offering “ the descrip- 
tion of a repeating instrument upon a new construction.” 
That the repeating circle, introduced for the correction of 
imperfections in the art of dividing, should not be approved by 
Mr. Troughton, who has so greatly advanced that art, and still 
so actively labours to perfect it, cannot occasion any surprize- 
Even its form and general appearance are objected to by him, 
for it is stated to be “ of all the instruments subservient to geo- 
desy and astronomy, the most uncouth and unsightly.” He 
adds, ‘‘ the whole of the effective parts are placed on one side 
of its single supporting pillar, and on the other a weight almost 
equal to the instrument, is placed for the purpose of keeping it 
in equilibrio. But ugliness is not the worst thing that attends 
this unavoidable combination ; for it renders the instrument 
top-heavy, tottering, and weak. In these respects, the azimuth 
