New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1859-10-08
SCIENCE. INDUSTRY AND LNVENTion

ao,iv. power. b7se ven:il.,ion. &c, by ussssa
ar COZ pressed by large stationary stsam<ns'hes ~
conveyed thrcugbou, TIE city IN pipes 10 De iAi
The streets fer that purposs i attracting oonsss
able attention anosg cur spectators, il may be ~
~ co,,;der some Of I've dfiicute. 20 be encounts1
IL ecoro uic.lly effe ,ng 50 desirable an OBJECT
|. The SIZE Of the main pipes vill OF oou-e, cePesa
On the amount Of pressure or oomps,,n,s given ~
air 100 lbs. 70 the square ircb requdsg bu. BAT ~
diameter for the came quantity ~ q lbs, asi 90
motor. a given bulk Of CIR under pressure Of ~
lbs. is capable of giving something more than tvies
n. pover Of the same bulk, un'er pressure OF
lbs; ether thing, being equal, me greatest poss@s
con preston would give the mot economical resuna
Blu, the practical difficulties Of leakage 10 the pun
ard pipes, and the heating Of machinery f'on Ne
latent heat becoming sensible by cSmpressi'n. stdth
conss quen ,ss in elasticity together with tue imlpS
.ibil,y OF It's being icay sPped TO mschinsy
under greet compression, must render hisa presses
.ess pisc.ieable AID more expensive than los.
Again, the tizs Of the mains must Of cOune, d.pssi
on the velocity and quantity Of sir forced 'arosyt
them. and Is the friction-which VII ia loog Ppeshs
considerable item in the resistsncs offered 70 u
condensirg pump -increases 10 fluids a. the squs'cd
the velocity, very rapid movemen. will be iouh
inprac.ioable, herce slow motion and eore'penA'
ipgly large pipe will be necessary.
The quantity of steam elected from the eShau1
pipe Of 10 horse power engine. q. the average pro-
.ure u,ed in this city is about Il eco feet per hour,
10000 feet per day Of ten hours The same qusatV
Of atmospheric air, If compressed into ene-qaarterh
bulk-60 lbs. pressure to toe irch -~oald occupy.
round numbers oOoo cubic feet Of space, aud weigh
over 5000 lbs.
Fer purposes of blast, about Is 600 cubic feet OF ar
ia required for the combustion Of 100 lbs OF cos,
about IL 600 feet under pressure of four s,mospheseA
And for ventilation the entire air in an occupied room
should be changed every few minutes during the
whole "A hours of each day, The exact time OF course
depending on the size Of the room and number d
occupants.
These general IDEAS must show the folly Of enserics
into an enterprise Of this kind, for furnishing the Cy
Of New.York with motive power, blast, and vsntl<
tor until il is asceItsned that Broadway or sons
other street is vide enough to admit the diameter OF
main pipe of sufficient capacity. to economically COG
tain and conduct the material which msy be easily 10
| termiped, by careful mathematical calculation.
H. Leakage viii be found considerable ,emi uhs
expense sccoun. Of operating the ooncerns l, sim
possbs to make al the working p,rts of s,esnea'
CINE ge, feety tight without too much friction, aud =
air under the same pressure wi leak freely througha
sttsmtight joint leakage must necessarily occar, not
ouy in the copdensirg pump, but in every engine 10
which the air is applied, we'll at more or lsss 81
the connections Of the msn pipes. As air PUSHES into
vacuum or under considerable pressure into the
atmosphere, with velocity Of about 600 feet per 80.
cond, at number of leak holes though each may
he extremely small, when added together will b
found TO give area sufficient, with velocity Of
1900 feet per second TO discharge immense qusa-
| tity ofar.
| ILL., The loss of heat in the compression Of sir I'll
Tot only be loss of power, but will o,csson otbef
Iracti difficulties, which may be sufficient in thsns
selves to render high pressure impracticable. The
air.punp or condenser can only bs worked uodes
water TO keep it COOL while the eugnes for using the
condensed air, ubsss warmed by artificial heat, wit
become 90 cold az to render their fabrication difficult
as an intensity Of cd may be pro ucsd by the eIpsa
zion of conpressed air much greater than the coolest
weather in Winter. has been practically demonstrs-
ted, by freezing blocks Of ice foot thick in New
Orleans in Summer when the Thermometer indicated
| temperature of 9O0.
Could 70 desirable an objsc; conveying through
our streets an economical safe and convenient motor
ventator and blast be effected it would be desiier
alum second only in magnitude to those necessites u
city life which We now erjoy-w1er and gas. Bot
we think fair ard thorough mathematical cslculs-
ton would give an approximation TO the quantity or
air required the best amount Of compression and loss
of power by friction, leakage, and otherwise, that
| would at once show its impractcsbity.
NV MyTHoD or TEsrISs SUMMARIZE TgLE-
GRAPH GABLES At the present moment there 10
naturally great amount Of interest felt in all mat
ters connected with submarine tslegrsphic cables,
and We constantly hear Of new methods being pro-
posed relating TO the same. One Of the most re-
cent well as important communications upon this
,ubjeet lie that which has been msie by Mr..
Reid, in England and it is particularly deserv-
ing Of attention, inasmuch a. by adopting the plan
proposed much disappointment as to the opcrstoo OF
the cable may b prevented while a. the same time
useless expenditure, both Of time and money, would
be avoided-the cable, by Mr.. Reids plsn being
thoroughly tested to its capsbility Of resisting
pressure before /. leaves the mandatory. Messrs.
Reid 81 Co, not content merely with submerging tho
cable and then applying pressure, subject i. to a
process Of their invention, during the operation