The Princeton union. [volume] (Princeton, Minn.) 1876-1976, 1879-03-12
Scientific Gossip.

Arsenic in the green leather lining of
the helmets worn by some soldiers at
Konigsberg caused troublesome erup.
tons,
A coating of soluble glass on caoutchoue
tubes will, it is said, render them imper-
vious 10 coal gas.
Lead has been found by Schulzenberg-
er In new and remarkable condition, and
he cites this as another example of allo.
tropism by electrolysis.
M. Depelly, in LES Mondes, proposes a
continuance by which the date when the
letter passs through the post Office will
be made to appear not only on the enve-
lope, but on the letter inclosed.
DR.. Carnelly finds that of 81 elements
20 show that the coefhcient Of expansion
increraes as the melting point dimlnishes.
The five exceptions are arsenic, anthony,
bismuth, telurium, and tin.
Following up the Investigations Of Dr..
Draper on radiations, M. Crova has
selected certain number Of de-
terminate wave lengths between the
Fraunhofer lines B and G, and has meas
ured the intensities of the radiations cor
responding to them from the sun, the
electric light, the Erummond light. ans
the moderator lamp. He found the
weakening of the intensity toward the
violet was very different in different cases.
In the solar spectrum it fell from 1000
to 460, and in tie moderator lamp from
1000 to 81 for the same variation of wave
length.
An interesting paper On the effect of
the motion of the air within an auditor
ium upon its acoustic properties, is con-
tributer by W. w. Jacques, Fellow in
Physics of the Johns Hopkins University.
to the Journal Of tie Franklin Institute.
Preachers, singers, actors, and public
speakers generally will find valuable sug-
gestlons indicated by it. Mr.. Jaques has
repeated Tyndallfs experiments with
some notifications, and arrived not only
at the conclusion that currents Of air
of var wing density form one of the chief
obstacles to the propagation OF sound.
but that they actually modify the sound
wave, and so give rise to great indist1nct-
ness.
A report on. street rails, presented by
Charles B. Dudley Of the Pennsylvania
Railroad Company, concludes that with
our metallurgical methods high Pies
phorus lover O.10 per cent? is inconsistent
with safety; that silicon should be as
low as is consistent with the successful
working of the Bessemer process (not
above O.O4 per cent. J that the best range
for carbon is from O25 per cent. to OBS
per cent; that the total of the hardeners
expressed in phosphorus units should not
:. be above 81 to 80, nor below %; that the
tensil strength shoul3 be $4,000 pounds
per square inch, and that the percentage
of elongation should be above 20 per cent
Mr.. John Hammes has reported to
Rear Admiral Rogers, of the United
States Naval Observatory, that on Nov.
10. 1878, $50 P. NJ. civil time, he saw a
volcanic eruption on the moon. in the
vicinity of Baco, Barocius, and Nicolai.
, while looking through 6-1 2-lnch tele-
, scope, at Oska.oosa, Iowa. The matter
elected took fan-ike form aud Hammes
says the spectacle continued ior half an
t hour, and was seen BY him as plainly as
, .sany other mountain scenery in the moon
| is seen, and of the same color" Rear
Admiral Rogers has intimated to his cor
: respondent that his observation twill be
= attributed to some chance dust on the
glass, or to some error of adjustment, or
I to an accidental ght reflected from some
/ neighbours window, or to some other
s source of error :" sz#
At the meeting of the Franklin Insti-
I tute on Nov. 30, DR.. Isaac Morris, Jr.,
a exhibited modification of the micro.
phone for stethoscopic purposes. 1t il
d like the ordinary Belltelephone, but with
the magnet and coil replaced by metal
;. lie tube which can he adjusted endwise
l. by means of screw at the end cf the
handle. A small carbon cup is inserted
=" at the end nearest the diaphragm. II
the centre of the inner side of thu
# diaphragm another short tube is attsched
having also carbon cup. Each tube i
: connected to binding posts. A pcinte;
l. piece Of carbon rests on the two Carlo,
= cups. which are placed half an inch apart
# and the circuit is completed with Bel
2 telephone. This instrument is very del
# cate; but though the Philadelphia Co,lep,
: of Physicians have been favorably inn
i pressed by it, in certain positions il doe
J. not work we'll.