New-York tribune., 1876-02-15
APPLIED SCIENCE.

~ Il
C.o, erpvr rop LOCOMOTIVE BouERs.-Accord-
,nr To the Society of German Railroad Engineers.
the use of ca,tsteel for locomotive boilers has not
been SO satisfactory as was expected.
WArER-GIAss FOR WAsHING COTTON USED IN
CLEANING MACHINERY.-AccOrding to the hes-
slsche Gecerbe- BiGu, cotton that has been uSed loi
cleaning machinery may not only be completely
ccaused by treatment with water-giaSs Witnout
succtinp the fiber OF color, but II 10 also rendered
softer and nOrc porous, and consequently PieleiaVlo
e. new material, IL takes up Oily matter IuOle
Readily
CARBoN FROM THE ROoF OF A GAS REToRT-Mr.
A. McDoucall exhibited before the Manchester
Literary and Philosophical Society specimen oi
carbon obtained from the roof OF gas ietoIt ic-
sembng graphite ia its almost metallic Iuster' IL
WAS undoubtedly produced 10y the decomposition Oh
tie hydrO-csrDOa gases IN the hiteiSe i,"' VI V.'o
rrtorI: a;id il is suggested that Ito formation may
turoS some light that oi giaphito, 40 t'.t edO
s,aDce 10 always associated With loVNs 'A@U nave
been subjected 10 lSneOus action
Casing FOR SrFAM-PiFEs.-The German journal
OF Hoolea Manufactures giyesthe following ior casing
steam-pIpes Nix Idiler's eart that has been useo
md collected in SINKS for tins purpose as well as 10
prevent the filing of streams, with luly the sahi0
onautitv of coal aud add to the pasty mass as
Iluc .is hair II Will take up before lay ''s Il
OH aud Onc-e snth Its quihuIy Oh caAOleH ~ P'uii
and lay III thin coats IL TIE hIe' LAY "a uo0S
DOt 0itilCIo wen, uAUsCN. l1iiCA c'A 'i A"~J ~
1Or 1t.
COxDUCTIoN OF ELECTRICITY By COMPOUNDS OF
notwithstanding TO the observations OF herwlg
the resistance which IRON and steel oier u ti'e
passage OF the galvanic current varies with the
direction intensity, and duration OF the curIeh'
itself Similar phenomena have now been made
known from the observations of Braun III reference
TO large number ci both natural and aItinciu COM
pounds OF sulphur; tie effects III question amount 90
80 pei cent Oi then cn,Ile Na!ue, 80 ttaV oI ule
existence Oi these differences tcie can pc ho qus
ton. a connection between inc ciA iAsldio7i"pHIS
pecuiiaritIes of the mnIcIaiS and Inc dhccuoh va
maximum OF minimum gaIvahlc RESISTANCE ls hot
clearly made OUt, although h'"4C'VN" !" 0''''O N~
COATING MIRRORS WITH AN ALLOY OF GOLD AND
PIAriNUM.-Fye hundred grains of sponFy platl-
NUN are dissolved in 80 cubic ccntimeers Of hydro
chloric and 30 of nitric acid, and the mass is evap'
rated 20 dryness. 1t is then powdered and dseSteC
with 1000 grains of essence of lavender 100 grains
of turpentine. and % grams Of suphurctted tm-
pentine resin (bQaRc Ne SQUIRE tcre6eRhinG Thirty
grains of gold made into chloride, are dissolved IL
800 cubic ceItimcters of wafer ana an equal &inoti
OF ether. The liquid i shaken, aud the Cthc!cd
solution added 10 the platinum aud allowed to eydp
orate spontaneously. Fifty grams Of lltdiugc, 20
grains oil lead bOgate, ana 100 grams oI lavender "
arr then added, and the mixture Is shaken, after
which the mirror Is coated WitG u. ana KEPT at q
red heat Till the composition IS burnt H.
THE SOLAR PARAILAX.-Prof. Gale, who has ell
deavorcd to calculate the solar parallax from OBJ
seryations of the astcrold Flora announced rs the
final result of his computations S".S79 Is dedl eco
from 3G southern and 81 northern stars, the Iii
trbuton Of the comparison stars being as favorable
H. an accurate result it is possible The creates
probable error that can ascrbe to this result 1,
the 5 Of a second. But IT is very remarkable, If We
divide his 73 equarions into three sections or or2
observations each, that dcdUce tie following
values, viz: S".9G, S"sG, and s".7S. The whole
compatation will al some fGtGTc time be published
In fun hut Prof Gale states that he has come 10
the conclusion that accurate result with so small
probable error could only have been accOTp shed by
the kind cooperation of the ObSeryatOucs Of the
Southern mi,phcre, and that even - u better
approximation can perhaps by, tils method be at
taimel in tie future To this end the observations
should If ever repeated, he male with the lareeS'
telescopes using the highest maglitylu@ power.
As constant or Onc~id.d cTTC,s eau be eliminated ~
a proper arrangement of the observations ot IL"
stars Of comparison. it becomes more important to
dniuish the eject of accidental errors by a IdlEc
incrraac In the number of observations. IL IS intel
eS,int To aid hat the preliminary results OF the OBJ
scryations Of tho recent transit Of Venus rs pre-
scntcG to the P;Is Academy OF science, agreed COM
pletelV with the Igur,s dcdutcd ht DT. Gdae.