SCIENTIEIC SUMMARY. 
87 
of meteoric bodies revolve. It is not unlikely that in tbe rich store of 
cometary record which Mr. Williams has lately enabled us to consult, 
several other appearances of the meteor-comet of November may be recog- 
nised. At present I have only succeeded in finding one, in addition to that 
of 1366, and in this case it is the European Chronicles which put us in pos- 
session of the track of the comet. In 868, at the end of January, a comet 
was observed under the tail of Ursa Minor, which moved in seventeen days 
almost to the constellation Triangulum. In China, it was seen in the 1st 
Moon (February), with the same right ascension as stars in Aries and Musca. 
I find, by calculation, that when Tempel’s Comet arrives at perihelion at the 
end of March or early in April, it must follow this path in the heavens, 
being first situated at the end of January in the constellation Camelopardus, 
when, for want of conspicuous stars of reference, it might be said to be below 
the tail of Ursa Minor, afterwards moving to Triangulum and Aries. 
Between 1866 and 1366 we should have fifteen periods of 33.28 years, and 
between 1366 and 868, also fifteen periods, of 33.34 years.” 
BOTANY. 
The Age of the vast Sequoias. — Professor Asa Gray, in delivering his address 
before the American Association at Iowa, naturally dwelt more especi- 
ally on botany. He gave a valuable lecture, in which he pointed out the 
more remarkable features, botanically, of the American Continent, and as a 
matter of course he dilated on those singularly aged trees the Sequoias. 
Concerning them he asks, Have they played in former times and upon a larger 
stage a more imposing part, of which the present is but the epilogue ? We 
cannot gaze high up the huge and venerable trunks, which one crosses the 
continent to behold, without wishing that these patriarchs of the grove 
were able, like the long-lived antediluvians of Scripture, to hand down to 
us, through a few generations, the traditions of centuries, and so tell us 
somewhat of the history of their race. Fifteen hundred annual layers have 
been counted, or satisfactorily made out, upon one or two fallen trunks. It 
is probable that close to the heart of some of the living trees may be found 
the circle that records the year of our Saviour’s nativity. A few genera- 
tions of such trees might carry the history a long way back. But the 
ground they stand upon, and the marks of very recent geological change and 
vicissitude in the region around, testify that not very many such generations 
can have flourished just there, at least in an unbroken series. When their 
site was covered by glaciers, these Sequoias must have occupied other sta- 
tions, if, as there is reason to believe, they then existed in the land. — Silli- 
marCs American Journal^ October 1872. 
Do Habits of Plants change with Climate ? — This question is answered by an 
able paper of Be Candolle’s, in a late number of “ Archives des Sciences.” 
He details a series of investigations of the question whether the habits of 
plants are changed by the action of the climate acting through a succession 
of generations. For this purpose he obtained seeds* of plants which are 
widely dispersed over Europe, from different localities, Edinburgh, Moscow, 
