TRANSACTIONS OF THE SECTIONS. Ρ 
17 
are two carriers, through which ἃ micrometer-screw having ten threads to the inch 
passes. 
On the screw, between the carriers, is a brass nut 34 inches in diameter, 
whose periphery is divided into a hundred equal parts, therefore the screw (being 
prevented from turning by a pin projecting into a groove in the piece supporting the 
carriers) will advance through a space equal to 
through which the nut shall be turned. 
to support the rod, in a direct line with the apparatus. 
zoos Of an inch for each division 
Pieces of wood are placed on the hand-rail 
The expansion has been 
ascertained in each case from experiments made on the same day ; consequently the 
apparatus could not have altered materially between the compared experiments. The 
tables exhibited show the average expansion of the substances enumerated, deduced 
from numerous experiments made at temperatures between 30° and 150° Fahr., but 
as none of the materials expand in a uniform degree by equal increments of tem- 
perature (in some of them the expansicn is very anomalous), the author purposes 
extending his experiments, with a view of ascertaining the amount of expansion due 
to every 10° of temperature, from 30° to 130°, or 140°. 
TaBLE I.—Linear expansion for 1° (Fahr.) of the undermentioned materials, obtained at 
temperatures between 30° and 150°. Average of 60 experiments. 
Zine, cast...... ἜΜΕΝΕ ΤΆ ΕΠ 21385 || Bagnall’s common iron .........++ 08503 
MRICS GIES: «ct dys capwavdsideeessnese ss °17714 || Daw’s best ditto ..........cccccceeeee | 08481 
Block tin; ΤΠ. s.aco.s.c<assocesees 10 θ Ow MMOL τὰν ΠΣ τ | 08452 
Black tin, Cast,......<cssaseeseseceser 16280 || Eglinton, Clyde, and Glenarnock | -08108 
Muntz’s metal........-.....4+ eye SP ΘΟ ill SUCEl CASU τε, τα ΤΑ ΤΣ veld cthas cease | 07746 
ΕΣ CITAWI .chsscsosteesecsceuss πα ΤΠ ον ΠΝ |) SaeEls SHOAL Εν ΟΕ ΠΡ "7074 
Brass, Watch .......-...00s- Peeper BSA *12585 || Langloan (CI. No. 3) ...........006 | 07581 
Gun-metal ............ us detlasianad aise 12738 || Langloan, ditto .................006 07499 
Copper, Grawiis....5..000ssessesseees PLZ ESQ GIAsss SQUCL ....« ον susecanveeesecjesete *05392 
Copperyieashiosiecccccssiweccvacts so PLU UL Glass, tubes. ..2.adccscasesss ovsece .... (05144 
‘Tasie 11. 
Dulong and! 
Gen. Roy, Petit. |Troughton.| Smeaton. | Lavoisier. |R. Roberts. 
Glass, flint ...| 4311 | ‘04788 | ......... *04629 04509 | -05268 
teed recess Ἔ BOO IOE | is ars os na 06610 | 06805 | °05993 | -07710 
Tron, cast...... *06170 | 06566 | ......... “06988.)| ......... 07729 
Iron, wrought ἘΣ ιν. τιον ὍΒΟΟΘΟ | ......... 06865 | -08478 
OPPEr.......0- eae 09545 10660 | -09444 | -09569 | °12121 
TALS BRS ease [Nae ἀξ | Pgeeaee ‘10660 | -10416 | -10370 | -12892 
LT ye Aa ἘΣ ere δ τος ΕΟ δ εδοΣ 2072 | °17832 
Zine....... Sa pete ΡΥ ΓΕ ΝΟ bcacelt ria conc .19549 
ΤΆΒΙΕ III.—Amount of expansion and contraction for 1° (Fahr.) of the wooden rods, 
obtained at temperatures between 54° and 90°. 
ine, St. John’s. | Pine, varnished. 
Cedar. 
Cedar, varnished. 
Expan. |Contrac.| Expan. |Contrac.| Expan. |Contrac.| Expan. 
Baywood. Baywood, varn. 
Expan. |Contrac. 
Expan. |Contrac. Contrac. 
ΤΙ 03788). ἘΠ ΠῚ '-01836)......... 06773). ..00c00s 03444)......... 06429]......... 02525] Fine. 
seeee++.-| 00366) -01465).........|-01343].........|(O1343)......0-/. cee. -00366| 02442)......... Fine. 
| 01612! -02357]......cc-leccccceee -01612| 00992|.....c00-|. e000... -01116| -01861)......... Cloudy 
eet 01214)...... οὐ νέοι 00506] °01417)...,.....|.2.+++-.-| (00809) °02125].........|Fine. 
-01895),......-+| -OO111).......4|-02898).........|-OO1111.........] 02786] -00334]...... ἐφ λᾶς 
02497 -00000)............... vs] 2996)... ἁενννν .Ὁ1098).... «νυν -03096)..+...+++ -00998|Ditto. 
02591)......... 00585].........|°03927].........] 009191......... -03428| Ὅ0586 ....... ..|Ditto. 
00809 -12749| -05036| -02532| 1343 -18712| -03752 05572 |......... -18030] -07347| 03523 
00809) 02124! -01259| 00844! -01343} -03118| 01250 ᾿01598..:...... .02575, -01469. -01761 
‘ The figures in all these Tables require four ciphers to be prefixed to them, 
1850. 
Cc 
