New-York tribune., 1868-02-19
SCIENCE.

To DESTROY INSECTS ON Fruit REEs'nnat ioss that
writer In The London Journal Of Hoyt.S"S ood & anTfi
as wash viii destroy the woody aphis ana osnes SSys
fruittrees efeetualy thin "a ~, Iaf mr.
Wash or any other compound generaiy useu ioi 9"'P
pose.
PAPER BELrs.--The latest nse to which paper paper
has been put its substitution lEa The new be
sfs Of ayers OF paper ceDented together IN such
peT as 20 9T These who have tried dnng the last
six months report that IL does not stretch ana on scc0u"
Of its cheapness it is preferred for light machinery
PACKING FOR STEAM JOINTs.-Mr. j. a. NIL
leT has remeded difficulty long experiences % i4
in keeping seamonts tight Tor dong gbin sieet OF
muslin between the fanches Of the pipes we nc % afn
yiousy painted The muslin Is P from blowing
M out, which is usually the case Tnen pa PAIN m as pera
The paint preserves the cloth and thus lnaAeS P
nent packing. - of
ADUITERATION OF DYEs.-A correspondent enc OF
TIE London Chemical NceS says that comn1
ehcmicsls 1or dysins tits well known that 10 uye an an
even fast and brilliant shade the insonhie in the
held IN state Of perfect solutions or @ be sioSv and
nest possible SUSPENSION so that Il may b oe S,oSy 1 ~
gradually delivered 70 the ecn the solvent and the
@er and eanses the latter to be rapidly and Tregaary
Ne ~ essv removal Ground tumeric Is another art
sie often with salt which paTs S 70 II o &
t in this is very similar to what has been pre-
ViOusly described.
CoRRosIoN OF CAST IRON.-1he London
oroI "Epqeering gives Grace Calvert of Manchester
fhe credit of making time SINCE series OF expert
ments which resulted in the discovery that cast IRON u
der certain conditions, undergoes loss OF VI
cohesion without corresponding alteration Of volume I
sizein other words, becomes rotten Mr. Malet hgw
ever commenced this investigation and deserves agner
place than Calvert in this connection The phenomenon
Is entirely different from common oxdson m Ton OK bT
ally reducing its size and c0rrespondiDgy 9
strength while the interior portion remains intact MT
Calvert immersed eastiron cubes eaeh one ~
dimension, in acdulaed water Each eoOe was place9
by itself in oOrked bottle filed with 80 centmeters OF
very diluted acid Among the acids tried were sqphnr1e
hydrochloc, and aeeo their action upon the IRON was
Saggs %hsteVer After three months Of contact it was
found that Of the cubes, and particularly that i'm
kneblade could penetrate three or four millmeters
deep The solptions then Eemoys1 and ,e"sesa oy
fresh acid Of the same kind IN each bOttethis REMOVAL
being continued every month for years After this
length u po changes had been effected In almost all the
cg the be 5SaS 6 S9s R S %C SCe c
In energy came hydrochore then suphnric aclc fn4s
phoTio acid showed NO similar action The result OF he
action Of other acids complete change in the ma
ture Of the metal without any alteration SL i.s Dx "
gray castron cubes was reduced from 1858 to 275 On
aDayLng the cube which had been IoF "
Of gray cast iron Of the same qualify as that composing
the original cdbe, Mr. Calvert found that the qusnuy
of phosphorus from OO5O OF sulphur from o17S
TO O6; while the amount OF earDon had increased from from
p47s to co., Sea water contains the elements from when
The destructive acids mentioned may De Tresn @ tH H
snoh water. The gradual deterioration OF CERTAIN kus
cast IRON exposed TO water may be considered
as established This action is Of course extremely slow
vet it should be taken into account in all engineering
structures relying for their safety upon cast iron in con-
tact with sea water any water which is the receptacle
of acids. The experiments by Calvert eOnfrm Ihose
made several before by Maet who found that the
eorosOn Of cast iron depended upon want OF l hono
of surface, density or hardness or the I'M
perfect combination of the carbon with the rOn Inc
Institution Of Civil Engineers in London recently aus
Guessed this question great length, and cited numerous
eases where cast iron which had been immersed from 80
20 years in water, was found wholly una1ected
angles OF the iron sharp as wh they lett the
fOundeTy and wholly uninjured." Mr. VIM J. MeAlpme,
OorrOsiOn cast iron should be hard OF an even close
arain and with its carbon intimately combined ana not
3n the form of graphite Impure soft foundery iron will
cOrrOde rapidy grained gray iron will resist cor
for long period, while white iron, OF gOOd quar-
ity, Is nearly mpershabe.