SCIENTIFIC SUMMARY. 
173 
the jaw strikingly resembles that found in the caves of Engihoul near Liege 
in I860, which, from additional evidence was referred by M. Hamy to the 
race of Cro-Magnon, and this identification would lead to the Nice jaw being 
referred to the same race, along with the skeletons obtained by M. Riviere 
near Mentone. M. de Quatrefages finds this identification supported by two 
fragments of bone which he refers to the right femur, and which str ikin gly 
present the strong longitudinal projection ( tinea aspera) which is characteristic 
of the men of Cro-Magnon. This race consequently lived in the Quaternary 
period both on the shores of Nice and among the mountains of Perigord. 
ASTRONOMY. 
The real Lihration of the Moon. — It has long been suspected that from 
its slightly ellipsoidal figure, the Moon undergoes a real libration, or slight 
periodical inequality, in its otherwise uniform rotation on its axis. Several 
attempts have been made to determine the amount of this real libration, but 
without any great success, though it is known that it must follow certain 
well-ascertained theoretical laws. Indeed, the theory of gravitation enables 
us to calculate the theory of this real libration with all desired accuracy, it 
only remains for observation to determine what is its actual maximum 
amount ; for this depending on the actual figure of the Moon is outside the 
domain of theory, and appertains strictly to observation. 
Lately, Herr Dr. Hartwig, of the Strassburg Observatory, has made an 
important addition to our knowledge of this subject by an elaborate 
memoir entitled, Beitrag zur Bestimmung der Physischen Libration des 
Mondes. He has employed, as the foundation of his investigation, forty-two 
measures, by means of the Strassburg heliometer, of the distance of the crater 
Mosting A, from seven points in the limb of the Moon. These measures 
Herr Hartwig proceeds to reduce in practically the same manner as employed 
by Herr Wichmann in his famous investigation of the year 1847, using 
exactly the same theoretical basis. The main results obtained by Herr 
Hartwig, and those previously obtained by Herr Wichmann, are appended : — 
Wichmann. Hartwig. 
Latitude of Mosting A . . = — 3 10 21 ± 11 = — 3 10 55 ± 24 
Longitude of Mosting A . = - 5 10 57 ± 25 = - 5 13 23 ± 89 
Inclination of the lunar equa- 
tor to the ecliptic . . = 1 36 34 ± 113 = 1 39 9 ± 250 
So far the results are not very discordant, and the small probable errors 
indicate the superior trustworthiness of Herr Hartwig’s results. The effects 
for the real libration may be written as follows : — 
Real libration in latitude . = + 17 sin { 13*188 T + 80° } according to Wich- 
mann. 
= + 295 sin { 13*188 T + 80 } according to Hart- 
wig. 
