New-York tribune., 1874-04-27
APPLIED SCIENCE.

at rest, tne lelteI y, anu Ciaiutu w PV
advantages over its predecessors These are s'a'ou
20 he absence of vibration; reduction of wear ana
tear to machinery ready adaptablity TO any scre"
steamship: and facility of checking n ships way,
with the power of driving her iiu seeu or
few seconds on reversal, rs we'll as giving oonslGea
ahla increase of sneed and affecting great SAYING
of coal During trial with the steam yaCno Ipb 10y
wing nnder pressure of IS pounds OF steam. WIN
n nnnsmnontion of 81 pounds of coal per hour, the
oroneer made 20 revolutions per minute Win tIio
tide slack and the furnace burning hard steam 0oai
the measured mule beng run III h'e minutes
HoorRRrNK METHOD OF FERTuIZING PLANTS
process invented by Hooibrenk for facilitating
the fertilization of plants has lately been success
fully tried according to les Mondes, in the Botanical
Gardens of Vienna. This consists in simply touch
ing the extremity of the stigma Of the flower about
10 bloom with a brush dipped in honey, or, stlll
better, in honey mixed with the pollen of the plant
10 be operated upon. THIS in the case OF Hibiscus
Mexioans which had never borne fruit, resulted 10
the production of perfect seeds The operation mas
succeeded very well with certain fruit trees, some OF
which have thus been caused to produce frut lor
the first time. As explanation Of this result II is
suggested that the honey keeps the grams OF polen
npOn the stigma and thus favOrs the development
OF the pollen tube which is Indispensable TO teru
ization The substitution of gyceTine toI money III
the experiment has been suggested
TIN MAGNrTrzArToN OF GIAss.-An interesting
paper in Poggendorfs ARnalen, by Prof. wharf,
treats of the time that flint glass takes to be mag
netized demagnehzed. and TO turn the plane OF
polarization He rotated glass cylinder between
the poles Of an electromagnetic where 1t acted ike
cylindrical lens with polarized light passing
through the poles. When not magnetized, the
cylinder whether IN motion at rest, was neutral
TO the hgnt: but when maenetized its plane Totat-
ing power diminished considerably, with IhcleasirtE
velocity of rotation the reason beng tnat, III t sun
quick revelation. each diameter remained 700 snort
time in the axfal direction to acquire all the mag
netism il would otherwise have. To gave lilnt gaSs
such tlIa~magnetc intensity as became OpsefNtoIs
Nv rotsfon of the plane required at least 1900 Of
second Of time while to give 1t all the dla-maghe-
ism it is capable OF taking under strong mashe''
at least l-4O0 Of second was needed
Friction WITHIN RIFIED GUNs.-Prof. Reynolds
of Manchester has presented an interesting memoir
on the relative work spent in friction, IN giving TO-
tatiOn 10 shot from guns Tifed with an increasing
and also with uniform twist he shows that the
friction between the studs and the grooves consumes
more work with an increasing than with UNIFORM
twist and that in the case Of grooves which develop
into parabolas, such as those used in the Woolwch
guns the waste from this cause is double what it
would be if the twist were uniform Among MS
conclusions Prof. Reynolds states that when the
pressure of the powder is constant the work spent III
friction in the OF parabOhc grooves is j. times
that spent in friction with plain grooves and that
this ratio becomes two when the pressure dimln-
fishes rapidly the ball moves along; and finally,
that this ratio NAV have any value between u aud
p but that II cannot g. beyond these Aml'S'
GERHARD PRoCEss FOR OBTAINING PCDDLED IRON
DrRrcr PROM THE ORE.-Nr +. W. Gerhard OF Stat
tordshire has lately introduced n new process by
which puddled iron is obtained direct from the ore,
the blast-furnace being dispensed with. Instead OF
using pig-ron, Mr.. Gerhard employs compound OF
ore OF any substance containing iron, the necessary
fuxes aud the equivalent of carbon. lump of this
compound is put into the furnace, and by the single
process known to the pudder as baling," " heat"
may be obtained in much less time and with corsd-
erably less labor than under the old method; the
process of "meltnQn and boiling" being entirely
dispensed with. The special feature Of the inven-
tOn Us the great saving Of fuel, II beng estimated
that 1GO pounds of coal saved in manufacturing
24lO pounds of iron. In the opinion of some iron
workers this method of making wrought iron must
very supeIscde the present laboTious and costly
mode of manufacturing 1t from plg-lrOn.
Pp1zr FOR AN Essay ON THE PoTATo DISEASE
The Royal Agricultural Society of Great Britain,
through the lberaty of Earl Cathcart, was enabled
10 offer prize Of G1O0 for the best essay on the
primary cause of the potato disease and the best
methods of it's prevention. Nnety-four essays were
sent in for competition, none of which, however,
was considered as satisfying the conditions. Among
the principal causes adduced by large majority OF
the writers as bringing about the disease were:
First the degeneration Of the tuber second, fungus
OH the tuber third, wet weather and generally
uuperabundaut moisture; fourth, PerOnOspord IN
ftsinp attacking the foliage; fifth, electricity; and
sixth plethoric OF succulent diseased condition
of the plant caused by specific manuTes.
The remedies proposed were use of new sorts OF
potatoes for panting sleeping or kiln-drying the
tuhers previous to planting; of lime as manure;
clumpmg, Jumping, or hillock-g growing; bending
the haulm downward clear of the tubers; tying the
haulms upright, and other notifications of the mode
of cultivation; dressing with sulphur, chlorine, &C.;
cutting off tops on the appearance of the disease;
sowing disease-proof Sorts the use of lightning
conductors of various modes Of construction, and
the avoidance of the use of certain manures
In view of the unsatisfactory results of this
petition, the Committee have recommended that
sum Of money say Gl0O, be granted for the purpose
of indneing competent mycOlogist to undertake the
investigation of the ehistory of the potato fungus
iPeronospOra iBfesiuus. especially in the interval
between the injury to the potato plant and the
pearauce of the fungus in the following year and
that a valuable purse be offered first for the best
disease-proOf early potato; and second. the best
proof late potato and also. for the purpose
of encouraging the production of varieties
having the desired qualities that prizes be offered
for diSeaseproOf potatoes of new varieties, TO be
sent in for competition in 1878.
In summing mp the present state of our knowledge
Of this disease the Committee state that the natural
history of the potato fungus, from the time it at
facks the foliage until the potatoes are harvested is
now well known, but that we are entirely Ignorant
of what becomes Of the parasite from the potato
harvest until its TeappeaTance the following year ;
therefore the latter portion of it's history offers
suitable field for ngesti CATION
The hope that varieties of potatoes may be found
practicaliy diSeaseprOOf is based upon the assump
fion that there is definite period of incubation of
this disease at certain seasons. and that certain
varieties reaching maturity before this period or
after il has passed. may avoid ITS attack
VIENNA CONGRESS OF LAND AND FOREST CUI-
TUmsTs.-Among other features of The Inter
national FxDosition at Vienna was "A Congress of