1830.] 
Notices of Books. 
231 
fact is sufficient to enable us to appreciate the authority of the Royal Society, as a 
learned body, and the degree of distinction conferred by the designation of F. R. S. 
England, with a population of 22 millions, has 685 members composing her 
scientific academy, with 50 foreigners : France, with a population of 32 millions, 
has 75 natives, 8 foreign and 100 corresponding members. It requires little consi- 
deration to determine in which country the title of academician is calculated to 
confer credit. As qualifications for admission into the Royal Society of London, 
except the fee, nothing seems to be required, save a matter of course certificate 
from three of the fellows; when, if the candidate, as Mr. B. observes, be so 
fortunate as to be quite unknown, he is sure to be elected. Even if he be a person 
of some celebrity, and yet so anxious to become a fellow as to overlook the trifling 
inconvenience of being black-balled, he is pretty sure, on a second application, or 
at most, a third, to succeed 4 * . 
One of the most extraordinary parts of this work is the very singular and ap- 
parently complete exposure made of the observations given by Captain Sabine, in 
his work on the Pendulum. This work was printed at the expense of the Board 
of Longitude, and the Council of the Royal Society spared no pains to stamp the 
accuracy of them with their testimony. The circumstance of Government pro- 
viding instruments and means of transport for the purpose of these enquiries, gave 
Captain Sabine advantages which do not often fall to the lot of the Amateur; while 
his great industry in observing, enabled him to bring home an immense mass of 
observations, and from places but seldom visited, at least with such instruments. 
The close agreement of these results, though not exactly what those most con- 
versant with the subject expected to see, — seemed yet to others creditable to one 
who was so new in his career as an observer. Whatever the subject of enquiry, 
all other observers were left at a distance, and to many it appeared that Captain 
Sabine had some keeuncss of vision, or acuteness of touch, that it was hopeless to 
expect to rival. 
Among the instruments employed by Captain Sabine was a repeating circle, of 6 
inches diameter, with a telescope of 7 inches focus, and I inch aperture, made by 
order of the Board of Longitude, for the express purpose of ascertaining how far 
repeating instruments might be diminished in size. Captain Sabine, in his work on 
the pendulum, unequivocally stamps his approbation upon this small instrument, 
and gives it as his opinion “ that the disadvantage of a smaller image, enabling a 
less precise contact or bisection, and of an arch of less radius, admitting of a less 
minute subdivision, may be compensated by the principle of repetition.” He does 
not hesitate even to compare the performance of this minute instrument with that 
of the circles used in the French Survey, allowance being made “for the ex- 
tensive experience, and great skill of the distinguished persons who conducted the 
French Observations 3 . The results at Maranham and Spitzbergen are especially 
referred to, as obtained in greater number, and with every attention to accuracy. 
Mr. Baggage, in two tables, compares the deductions at the former place with 
those made by the French astronomers at Formentera, by means of a repeating 
circle of 16 inches diameter, constructed with special care by Forteu. In the French 
series, taking only the inferior passage of Polaris, the results of from 64 to 120 
repetitions have an extreme difference of 3”, 8. The greatest difference from the 
mean is 2”, 2. In Captain Sabine’s Series the results are derived from but 8 to 
12 repetitions ; the stars are all different, yet the extreme difference amongst 6 
results is 2”, 5, the greatest difference from the mean 1”,3. The natural inference 
from this comparison is, not that a repeating circle of 6 inches diameter is merely 
equal to one of 1 6 inches, but that it is decidedly superior to it. 
“ Fortunately for astronomy, as Mr. Babbage observes, long after these observa- 
tions were made, published, and rewarded, 6 Captain Kater having borrowed the 
same instrument discovered that the divisions of its level, which Captain Sabine 
had considered to be equal to one-second, each, were, in fact, more nearly equal to 
eleven- seconds each, one being 10," 9“ ! ! ! 
If now correcting for this strange error, we enquire what would be the results at 
Maranham, “ which were obtained with especial regard to every circumstance by 
which their accuracy might be affected we find that instead of the extreme differ- 
ence from the mean being only 1 ", 3 “it is 12, "while the difference amongst the re- 
4 Mr. Babbage mentions, that during 14 years’ experience he has had of these 
matters, all the candidates rejected were known persons. 
3 Vide our number for January, p. 9 et sequ. 
6 Captain Sabine obtained one of the medals of the Royal Society, and a 2nd from 
the French Institute for these observations, 
