New-York tribune., 1874-08-01
APPLIED SCIENCE.

CEMENT FOR RENDERING CoRKs TrGHT.-The
rorks should be brushed several times with mix
tnre of a solution of sheac of the consistency OF
sirup. prepared by the aid of heat and with SIM
liar solution of caoutchouc IN benzlne, separately
prepared care being taken that one coat is peiecy
dry before another is lald on
POLISHING POWDER FOR GOLD ARTICLEs.-lhe
following mixture. applied by means of piece of
heather is highly recommended by Belgian gold
smiths for polishing true gold articles 4 pound OF
chalk 81 ounces of clay, of white lead Of
An ounce of carbonate of magnesia OF an 0nnce OF
polishing rouge all fnely pdyerzed and intimately
mixed.
TIE ASCENT OF SAP IN PLANTs.-Prof McNaD
has presented 20 the Royal Irish Academy neuion
on the ascent of water in the stems OF pants 10 III
vestigate which point very many experiments were
made He finds in the privet the rate OF ascent 10
be about 9 inches per hour in the elm 100 lnches
per hour in the cherry laurel the rate varied from
"a TO l3 inches Experiments were also made as To
the influence of sunlight and darkness. the influence
of the bark the influence of the leaves ana the III
fuence OF pressure.
EARTHQUAKES IN New -ENGLAND-Mr. Lancaster
in some remarks on Mr. Brighams catalogue OF New
England earthquakes states that during the laSt
three centuries the number of recorded earthquakes
in New-EpCland has averaged about two per annum
The maximum numbers of earthquakes fall IN FEB
rnary and November, the minimum III Aprl anu sep
tember. There are 16S recorded 10 nave occuleJ oi
during the entire period during the Autumn anu
Winter months. while only 81 are recorded IN the
Spring and Summer months
PREPARATION OF TRIPOu FOR POLISHING VAR
NIsHEp ARTIcIEs.-Very finely pulverized tripoll is
passed through a hair sieve and stirred well with
water with a wooden rod, and the water with the
fine trpol in suspension is poured into another YES
sel and allowed to stand for hour or longer until
clear and is then poured off. The powder obtained
by drying the sediment paper, IN the sun OF st0Nt
Is employed on felt OF flannel 1or posIng & @
lion if necessary and finally wping with anne clo'h'
TIDES IN THE ARCTIC OCEAN.-One OF the most
interesting results of the Polaris Arctic exploration
has been the deductions based upon the constant
and careful tidal observations that were made at
Thank God HaTbOr. DR.. Bessels says that II was
found that for that place the co-tdal hour is about
16 hours % min. Rensselaer, HarbOr, being the
northemmost station, has a cotdal hour is hours
min. Consequently the tide comes from the north.
The rise and fall at spring tides amountSto about
feet: at neap tides 23 feet Most likely the Atlantic
and Pacific tidal waves meet somewhere IN smith
Sound, near Cape Frazier.
Hooks PETROLEUM MOrOR.-In the imperial
printing Office at Vienna three presses of a capacity
of 200 sheets per hour driven by a motor In
vented by Hook which promises to be very useful
for small industrial establishments. Combustion
of petroleum IN the working cylinder, and the heat
developed by it, constitute the motive power. The
machine is said to be very regular IN action, TO be
sntlrely free from danger TO require little attention
10 occupy little space, and TO be very econ0mlcal IN
running. II pounds of petroleum per hour beng
reCkODed for One-hoTse pOWe" Like tne gaS-engl,le
ii is also ready at all times, and 1T is easily cooled
down.
DALMArIAN INSECT PowDER-It is stated by Prof
nd hot fln Lras1
mum has long been employed in Damata for the
preparation of powder similar to Persian insect
powder and that this widely difused weed is now
largely employed in Germany for the same purpose,
and, with the ChrysdnthenuR segetam, forms per
feet substitute for Pyrethram and roseum,
from which the Persian powder is prepared. These
facts may be Of sufficient importance to justify fur
ther experiments with these plants since Dalmatan
insectpOwder has recently been found very effective
against parasites sheep and cattle one pound OF
IT being equivalent III this respect to pound OF ar
seDlC.
ANEW CONTACT THEORY OF THE GALvANIC CELL.
The ll-knOwn electrician J. ii. Fleming has
hbted to the Physical Society of London
galyanc battery consisting of three test tubes of d
lutte nitric acid alternated with the number of
tubes of sodium -penta-suphide; ordinary we'll IN
suated bent strips of alternated lead and copper,
connecting with the neigboriug tubes. BY this de-
vice the terminal poles of the same metalS-all
contact of dSSlmlIar metals DeOg completely avoid
ed On connecting with coarse galvanOmeter the
needle violently and permanently detected
tested by the quadrant electrOmeter the potential
shown 10 increase regularly with the number OF
cells. The principle upon which the action depends
is that in the acid lead is positive TO "copper" IN the
sulphlde II is negative.
The MECHANICAL PERFECTION OF THE HUMAN
HEART-ar. Garrod. in interesting lecture at the
ROYAL lustitatiOn of London, the heart and the
sphvgmograph states that the heart is TO be viewed
apump constructed on the same principle an engine
built as indicated by hmseif and so regulated by
means of an elastic bag that the velocity OF the work
ing machinery does not vary with The work TO be
done. large number of measurements has enabled
him to show that the relative lengths of the systOs
and diaStOc portions of the pulse trace do not vary
for any given pulse rate but the blood pressure III
the arteries is quite independent of the pulse rates
whence il follows that the force of the cardiac mus
cular contraction varies directly the blood pres
1t may also be demonstrated that at least ap
prOXimatelv. the nutrition of the hearts walls must
vary the square root of the length of the dastoc
period.
THE ACTION OF TIDES on THE SEA BoTToM-Mr.
Reade communicates TO the Geological Society of
Liverpool the result of a series of novel nvestga-
tons on the action OF tides the sea bottom. He
shows that AT various points IN the St. George ana
English channels and in the Irish sea, tidal currents
capable OF destructive eroslve action on the
sea bottom, and that the materials of the Irish
bottom principally composed of rearranged
glacial drift either eroded OFF the bottom of the
coast by the itself, poured into Thy the many
rivers These materials notwithstanding the oscil-
latory character OF the tidal streams. have in the
main a slow progressive motion down the channel
aud far out into the Atlantic. was shown that
there are pits ulles eXcayated in the bottom III
both the English and Irish channels and that these
depressiOns generally have their mayor axes con-
fonnable IN direction with the set of the stream
tide. In conclusion Mr.. Reade expresses his conylc-