The workingman's advocate. [volume] (Chicago [Ill.]) 1864-1877, 1872-04-27

DR. BURG, IN reviewing the statistics Of
deaths from eholera, finds that out of about
22,,O00 artisans in copper, brass and bronze
employed in Paris and other cities during
'the last outbreak of cholera, only sixteen
deaths resulted from that disease Another
interesting fact bearing On this question is
that the city Of Mio TintO. surrounded as
it is BY copper mines. has never been visit
ed by this epidemic.
THE Flow oF LIQUIDS. Prof. Colding
gives, in the Copenhagen Transactions,
his Investigations of the Law Of the motion
Of water in pipes and conduits, and has
also applied his results to ocean currents.
His method 10 to determine the motion Of
liquid threads, that motion varying with
the depth when water flows over plane
surface The formulse nov generally used
are founded on the assumption that water
moves in plane layers nj uniform velocity.
These formuIse are known to be defective.
MANSA- Boussingault has given to the
Paris Academy of Sciences an account of
his observations on = mama obtained from
the leaves taken from near the top Of an old
linden, in the N0sges. Other trees Of the
same kind in the vicinity yielded no mamma.
The composition Of this mamma was found
to be about 80 per cent. of cane sugar, 20
Of glucose, and 10 Of dextrin. The mamma
from Mount Sinai, examined by Ehrenberg
and Berthelot, had nearly the same compo-
sition, and was supposed to be an eXuda-
ton caused by the pinctures Of an insect.
GUNPowDER GAUGE-The principle sug-
gested by Trescas e. .,eriments on the flow
oe Ia hol,aa -. haop hry M T..
Commandant de Reffye to the determine
ton of the pressure in the bore of large
guns. A cylindrical hole, bored into the
gun, is filed by block Of lead, supported
behind by a steel block, through which is
small cylindrical hole. When pressure acts
on the lead, a portion of it is forced into
the hole in the steel block. The volume
of lead found in the cylindrical cavity after
the gun has been fired is the measure Of
the pressure in the bore Of the gun.
BEssEMKR's GUS.-In the improved plan
for heavy ordnance by Mr.. Bessemer, the
initial pressure is reduced by having
series OF smaller charges ignited successive
" a the shot travels along the bore of the
gun. This N, however, the essential fea-
ture Il the American gun patented by Mr..
A. s. LYMAN. In order to secure the
greatest benefit from this method of apply
ing force, Mr.. Bessemer proposes to in
crease the length Of the gun to fifty feet.
1t is to be made Of wrought iron tubes,
connected by ianges and strengthened BY
steel rings Rotation is TO be Aiven TO an
elongated shot, not by rihing the bore Of
the gun, but by the reaction Of powder gas
issuing in small jets through tangential or
ifices at the circumference Of the shot. The
shot Is t. be made hollow, and contain the
charges Of powder required to rotate it.
The objections to Mr. Bessemer's i'm
provements are So grave that it may be
doubted whether he will carry them into
practice.
Mr.. L. BUDDE has described series Of
experiments which show that chlorine gas
expands much more under the action Of the
violet rays than when exposed to the red
rays of the spectrum. The same result was
obtained ON substituting bromine for chic
rine-thus revealing the new fact that some
bodies increase in volume under the actinic
rays. as others do under the heating rays
He offers the following explanation Of the
phenomenon
Ol Light may decompose the chlorine
moIecuIe into atoms. (2) The more re
frangible rays Of light may effect some un-
known change, which results in heat and
causes expansion. 49, 1t may be assumed
that there are bodies which increase ia
temperature more under exposure to the
violet than to the red rays. The author
regarding the first view As the most prob
able, believes the expansion Of chlorine Is
the effect Of a temporary separation Of
atoms under the influence Of the more re-
@Angible rays.
PRoF. TYHDALL, in a recent lecture on
the movement Of glaciers, after describing
the observations and measurements made
bv himself on the Mer de Glace, gives the
following clear statement touching the rel
alive motion II different parts of a crooked
river Of ice: When q glacier moves through
n Hinnous valley, the locus Of the point q
maximum motion does not coincide with
the center Of the glacier, but, on the con
trary, always lies on the convex side Of the
central line. The locus is therefore a
curved line more deeply sinuous than the
valley itself, and therefore crosses the axis
Of the glacier at each point Of the contrary
flexure. This law holds good for water,
substituting the word river for glacier.
The idea. then, as to the similarity between
\ river and q glacier, becomes marvelOusly
strengthened. The glacier is like river,
because the central part moves faster than
the sides; it ia like river, because its top
moves faster than its bottom; and again II
u Ike q river, because the point Of swIftest
motion follows the sinuoslties q rs sides