, 1879-06-14
SPARKS OF SCIENCE.
HOLLOW WALLIS IN BUILDINGS.
To the Editor Of 7ne Tribune.

is of tho utmost Importance. Nh builJlinr cnn
bo mato Thoroughly comfor,nhlo Without ihceo
eratum Is to 10 construct walls AZ to nroycnt ns
far MS possible The copYcctton Of heat tbrouph
them. To this end II Ie essential thnt uo uso
s,1cn material as has The 1cast conducting power;
relative conductivtty Of tbs different matcrjais
used. Nearly Mi t,,st-class buiidings >, have yts
their walls OF stone, brick, and NOR
tar, The cheaper buunrs. such ns
dwellings Of n moderately expensive kind,
arc usually built OF wood, and there Is ncThapa
no class OF buildings In which We live Ia the
eonstruc.ion q wh1cl, there i necessity for 50
III liz . rslaive ii % eondustng power Of the lrereut
building materials is as follows:
DsseS.
Plaster, ,,,,,,, -, -. ..,.,,.,..' I
Wood-less than. ,... 1
Wood, therefore. IL the best material named;
but woolen felt IA non much used tu place Uf
wDod, u,,d is probably better for many purposcs.
vars.us considerations, however, 1nay govern
our r4.oice and ucccssitutc Ills use OF stone or
6riek. When ills is tlic casc il is an excellent
method 10 fur the walls inside With ordinary
turing strips, then sheaihe or cover
iicsn With this wooirn fclt, md
agaitst the faco Of each furrln., and over tho
felt, fur aean for latl, md plastor, This is m
comparatively good uou.rol,ductor, mud, NTH
an air chamber on cacl, side oi it.-botncen the
brick and wood Oh the one hnni and the Iath
and plaster ou tt,. other--it Is perhaps the best
method OF preventing tpuyectlot, Of hcot
through walls Hollow brick walls arc eoulu-
times rcsortcd to- but 1t The TWO sections Of tho
walls are SO completely separated Us to entirely
break t1sc continuity of thu brick tic
walls arc weakened. 1t Is a pop
uIar error that wide space Or
alrc,,an,bcr IL hollow wull ,s better than
| narrow Que. This error Ia founded entirely on
| 4 nisconceptton uf What leat is, and low IL
| travels through space
Let us Investigate this part Of our subject md
see II we can prove the correctness of our poei-
STATIONS Is clesr as practicable, wv mll ass;,sno
| tint the material Of our building ia chiefly
| wood, and that 1t is desirable to
\ nreFnnt tho convection al hene M tut,rh
ss possible, For the illustration Of
princlptc, a.,d without reference 10 stnoitlsy
Of construction, W. will suppose our waiI to b.,
tuado Of . series Of close boIrd partitions set
lltiu distance apnrt to produco ehaml,crs Tor
these chambers viii be cquaily as oilIciunt ns
non.eun.lnctors % whether tl'cy Be- ons . or ten Gu
inches il. With
| For convenience Of reference we will number
| tIe nartIk{ons scparatl,yy these rt,ambrrs one.
iwo three, &c.
| A bean Of rars from the sun ID st,uply Il COL
Win n yejtrity Tint far tutstrins thn jpnt-
n,,,g. md 80 lonc as lcsu wHy,s
uro allowed. to continue Oh in tl<tE
tourney ,lniuteruptcdiy tIvro il no nurc I,cut
IN them t.al1 ~ aIe ley rsgtoas as @ ie potns, hgt
Mhsn lney 1hplnEe on our nhu!es' tneY. tnIonEh
thc incdlaM u our hefves anu ntasil. prnaiteo
tnG hehsa!,oh ~, " nGat. II tAcy nipAgu IN ul9
;s.'as Ma oi Ms sse' Mey psooace the sehs'a'aa OK
i'f.t. .. .,,
NOW, We VIII sIppose tnaf neam Of thesc
rays, or ether waves. snail impsnao on nc cx,
tcfiof u nnf naeasaFs notise, VIII ~ ooasl
a Ma!s a, aa ar sA'nes nua s.nMs1 ns enu ot
direction pcrpeGdlsnlar TO tle plane q. ot
tla hon1d; oa L. aaucn eIcater po.!som 81 ar
hram VIII bc npsoroeu aflu transmitted tnhh II
llnpinEe upou Inc y 9oars m ,ot,liquey; not IN
sasn os1'om o. , 9 peaMaepcnq1 h nng
OIL 'ss hnste ol lheiiehce-"n ~ ausuEpcu m ni!u
transmitted ~ accordance win tho iaWs q con-
Sccton, anu the remainder w! ne fesctea paek
INTO SPACE, or 70 t1c surrounding on1octs, 10 &c"
eorGanee Win tue laws o. reflection.
When this beam llaa itnninged upon tho snr-
facg Of this partition numbe: one, that portion
Of il1e heam ttlat " nbsorhcd enters Among tho
molecules OF The Wood, anu sets them
iii acttvo n'otson, one against another,
and now, for the first tine. our rnJs
bccone beat. itetore they inptngo gu the
ether. siuatlaE to wayc on the surfaco Of water,