New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1872-04-18
SCIENTIFIC NOTES.

TIE Flow OF LIQUIDs.-Prof. COlding gives,
in the Copenhagen Transactions" his investigations OF
the law Of the motion of water in pipes and c0nduts
also applied his results to ocean currents His
method Is determine the motion OF liquid threads,
that motion varying with the depth when water fOw5
over plane Surface The formula now generally used
are founded on the assumption that water moves IN
plane layers at uniform velocity. THESE iormuiD are
known to be detective.
MANNA.-Boussngaul has given to the Paris
Academy Of Sciences account Of his observations on
mamma obtained from the leaves taken from near the
top of an old linden in the yOsges. Other trees OF the
same kind in the vicinity yielded no mama The COM
position ~ this found 10 he ABOUT 90 per cent
OF sugar, Is OF glucose and 20 OF dexir, Inc
mamma from sit. Sinai, examined by EhrcnDcIS ana
Bertheoi, mad nearly the same composition, and was
supposed to be exudaon caused by the puncture oi
an insect.
GrNPOwDER GAUGE.-Thc principle sug-
ecstcd by Tresca's experiments on the flow Of solid
bodies has applied by ~ lie Commandment dc Rehye
determination of the pressure in the bore OF large
guns cylindrical hole. bored into the gun. is fed by
block OF lead supported oeind pS hale When
pressure the lead portion OF 1t Is forced INTO
The cylindrical cavity the gun has been fired Is the
measure OF the pressure i'll the bore of the gum
MINERAL CoTTON.-Mr Coleman Sellers Of
Philadelphia exhibited, at recent meeting OF the
franklin Institute, sample of product formed by al
lowing Jet OF steam to escape through stream Of
Y.
threads sometimes two three feet In length. These
threads Of glass readily break up into much shorter
hence the name The material is a slow conductor Of
heat and rs great quantities of air must be retained IN
ifs insterStccs 1t is well adapted Ia many purposes
where sO-caled non conductors OF heat are required
EFFECT OF FASTING.-Prof Seegan has COM
nuncated to the viennese Academy of Science the re-
suits of Investigations upon the meamophosis of tissue
during fasting The subject OF Ills experiments was u
Young girl who, consequence OF structure of the
csoplagus was only able TO consume very small guam
titles OF nourishment. During whole month her daily
food was but % grammes OF milk and about 90 cubic GEN.
timeteTs Of water. teaspo0nfu OF TINS mixture was
taken every After lasting four weeks the difficulty
of swallowing gradually disappeared. and the quantity
of milk taken daily rose 10 2l0 grammes. The author
gives full account of many interesting results obtained
only of which need be here stated namely; tHaG
the n.etamOrphoss of the abuminates which was prin-
the eXcreon of during fasting bears the proper
ton 10 the normal metamOrlhOsls OF ia or 10.
BEssEMER's GUN.-ln the improved plan for
heavy ordnance by Mr. Bcssemer, the initial pressure
reduced by having a series OF smaller charges gnited
successfully as the shot travels along the bore Of the
gun This Is however, the essential feature Of the
American gun patented by Mr. A. $. Lyman. In order
the greatest benefit from TINS method OF Apply
ING force proposes to increase the length
of gun to 80 feet. IL is To be made OF wrought non
tubes, connected by anges and Strengthened by steel
rings Rotation TO he given to elongated shot hot
by riding the bore Of the gun, but by the reaction vi
orces at the circumference OF the shot Inc shot Il 10
be made hollow. and contain the charges Of powder re-
II.
. Improvements" are grave that it may be doubted
whether he will carry them into practice
SINGULAR Action OF LIGHT UPON CHLORINE.
MI l.. Budde has described, in Pogg 4nnaIcn, No. TO-
1871, series OF experiments which show that chlorine
gas expands under the action of the violet
IN, than exposed TO the red rays of the spectrum
The same result was obtained substituting bromine
for chlorine thus revealing The new fact That some
bodies increase in volume under the actnic rays as
OF hers do uucr the heating rays. He offers the follow
ing explanation ~ the plcnGmCnO non: QJ Light may de-
impose the chlorine moecule into atoms % the more
refrangible rays OF light may effect some unknown
change which results In heat, and causes expansion. 81
i'm Temperature under exposure the violet than
to red The author, regarding the first view rs
the probable believes the expansion OF chlorine Is
the effect temporary separation of atoms under the
influence Of the more refraDgibe rays.
THE Flow OF GLhCIERs.-Prof. Tyndall
in a recent lecture the movement OF glaciers after
describing the observations and made by
himself on the Mer de Glace gives the following clear
statement touching the relative motion Of different parts
of crooked riyerof lee when glacier moves through
q sinuous valley the locus OF the point OF max imum
on does not coincide with the center OF the glacier but
central line. The locus is therefore curved line moro
deeply sinuous than the valley ITSELF and therefore
crosses the axis of the glacier each point OF the
trary hexure This law holds good for water substitut
similarity between river and glacier becomes mar
yelousy ghened. The glacier Is like river, be-
like river because It's top moves faster than it, bot.
tom and again IL Is like river because the point VI
sWilteSt motion fOOWs the hlnuOsltlcs OF us Sides.
SKELETON LEAvEs.-Mr. j. +. Robinson de-
scrbes In Hdrdricks heience Gossip q simple
method OF preparing skeleton leaves, which seems
nreferable To the old and tedious method OF
maceraton and which he recommends to all young bot
anists especially his fair friends. who take up the
science OF botany intelligent amusement than
for severe study First dissolve four
washing soda in quart OF boiling water. then add two
ounces OF slaked quick me and ron for about fifteen
ninues Allow the solution TO cool afterward pour of
All the clear liquor into clean saucepan When this
nuOr Ia boiling point place the leaves carefully In
the pan and boil the whole together for an hour, adding
from time enough water To make for the loss
by evaporation. The epderms and parenchyma OF some
lea will more readily separate than others. good
les. IL o try the leaves after they have been gently boil
ing hour and II the cellular matter does not easily
rub off betwixt the finger and thumb beneath cold
water boil them again for short time. When
M neshy matter found To be sufficiently softened rub
them separately but very gently beneath cold water
until the perfect skeleton Is exposed Tic skeletons at
lrst are of u dirty white color; 10 make them Of pure
white and therefore more beautiful. all that Is necessary
H. m bleach them In weak solution OF chloride OF Lime
a large teaspOOnful OF chloride OF lime 10 quart Of
wner drops Of vinegar II added To the solution,
in f. All the better for then the free chlorine Is liberated.
do not allow them To remain long the bleaching
1uor they become too brittle and cannot afterwards
he handled without injury. About IS minutes Will he
suflicicu make them white aud cean-lo looking. Dry
Me specimens In white bottng paper beneath gentle
simple leaves the best for Young begin
ners experiment upon the vine. poplar beech, and
ivy leaves make excellent skeletons Care must be
ercscd the selection Of leaves wen as the period
Of the year and the state OF the atmo phcrc when the
I'D cimcna Hio collected, otherwise failure Will be the
result. The best mouths 10 gather tht spec linens
July aud August. Never collect specimen, ~ damp
weather aud mono but perfectly mItuteI oiYc, ought
" bS selected