Scientific American Supplement, No. 810, July 11, 1891Various
Science
Scientific American Supplement, No. 810, July 11, 1891
Various
Science -- Periodicals
Minor views of construction and measurement and the deformations that
the instrument has undergone sufficiently explain the divergence of
11/2 deg. between the two results, which comprise between them the latitude
of Paris.
After doing all the reasoning that we have just given at length, we
have finally found the means by which the hypothetic bead was to be
put in place. A little beyond the curves, a very small but perfectly
conspicuous dot is engraved--the intersection of two lines of
construction that it was doubtless desired to efface, but the scarcely
visible trace of which subsists. Upon measuring with the compasses the
distance between the insertion of the thread and this dot, we find
exactly the distance, N P, of our diagram. Therefore there is no doubt
that this dot served as a datum point. The existence of the bead upon
the thread and the use of it as a rude calendar therefore appears to
be certain.
The compass is to furnish us new indications. After dismounting it--an
operation that the quite primitive enchasing of the face plate renders
very easy--we took a copy of it, which we measured with care. The
arrow forms with the line O C-O R an angle of 90 deg. + 8 deg.. The compass
was therefore constructed in view of an eastern declination of 8 deg..
Now, here is what we know with most certainty as to the magnetic
declination of Paris at the epoch in question:
Years. Declinations.
1550. 8 deg. east.
1580. 11.30
1622. 6.30
1634. 4.16
On causing the curve (Fig. 3, No. 3) to pass through the four points
thus determined, we find, for 1612, the declination 81/2 deg.. This is, with
an approximation closer than that of the measurements that can be made
upon the small compass, the value that we found. From these data as a
whole we draw the two following conclusions: (1) The instrument was
constructed at Paris; and (2) the inventor was accurately posted in
the science of his time.
Certain easily perceived retouchings, moreover, show that this sun
dial is not a copy, but rather an original. We are therefore in an
attitude to claim, as we did at the outset, that the constructor of
this pleasing object was not only an artist, but a man of science as
well.
Let us compare a few dates: In 1612, Galileo and Kepler were still
living. Thirty years were yet to lapse before the birth of Newton.
Modern astronomy was in its tenderest infancy, and remained the
privilege of a few initiated persons.--_C.E. Guillaume, in La Nature._
* * * * *
[MIND.]
THE UNDYING GERM PLASM AND THE IMMORTAL SOUL.
By Dr. R. VON LENDENFELD.
[The following article appeared originally, last year, in the German
scientific monthly, _Humboldt_. It, is reproduced here (by
permission)--the English from the hand of Mr. A.E. Shipley--as a
specimen of the kind of general speculation to which modern biology is
giving rise.--EDITOR.]
Public-domain text, read in full here on John Shaqi.
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