274 
MR. DANIELL ON A NEW REGISTER- PYROMETER 
Exp. 6. The expansion of the last specimen of black-lead ware being nearly 
the least which has fallen under my observation, I repeated with it the experi- 
ment of the dilatation of six of the former list of metals to the boiling point of 
water ; as the accuracy of these observations is a point which it is of the 
greatest importance to establish. 
The subjoined Table contains the results. 
Table VIII. 
Platinum . 
. 0 
22 = .00319 from 60° to 212 
Iron . . . 
. 0 
39 = .00566 
Copper . . 
. 0 
54 = .00785 
Brass . . 
. 0 
59 = .00857 
Gold . . . 
. 0 
41 = .00595 
Silver . . 
. 0 
58 = .00843 
The differences of the observed expansions and the real are also subjoined 
and ranged by the side of those obtained by the first series of observations. 
Table IX. 
Platinum 
Expansion of the Metal Bars. 
absolute .00478 
apparent .00319 
Expansion of Black-lead. 
Second Series. First Series. 
Differ, from Differ, from 
Mean. Mean. 
= .00159 .00000 . . .00202 -.00032 
Iron . . 
absolute .00640 
apparent .00566 
= .00074 
-.00085 . 
. .00132 
-.00102 
Copper . 
absolute .00930 
apparent .00785 
= .00145 
-.00014 . 
. .00247 
+ .00013 
Brass. . 
absolute .01045 
apparent .00857 
= .00188 
+ .00029 . 
. .00246 
+ .00012 
Gold . . 
absolute .00794 
apparent .00595 
= .00199 
+ .00040 . 
. .00242 
+ .00008 
Silver 
. absolute .01034 
apparent .00843 
= .00191 
+ .00032 . 
. .00220 
-.00014 
Mean 
. .00159 
. .00234 
