272 Mr. Daniell on a New Regtstei'-Pt/romcler, 



Exp. 3. Bars of the following metals were successively 

 placed in the register and immersed in hot water, which was 

 gradually heated to the boiling point, and kept boiling for ten 

 minutes in each instance. The following Table exhibits the 

 readings of the scale and the appropriate expansions. 



Table V. 



Platinum 0"=19' = -00276 from 60° to 212° 



Iron (soft) 



Copper 



Tin (grain) 



Zinc 1 



Lead 1 



Brass 55 



Gold (fine) 



Silver (fine) 



In the subsequent Table, I have given the absolute expan- 

 sions of the same metals from 32° to 212° from the best au- 

 thorities; and for the sake of comparison have added from 

 calculation their expansion from 62° to 212°, by reducing the 

 former in the proportion of 180 : 150. 



Table VI. 



Length of Bar. From 32' to 212". From 62' to 212". Authorities. 



Platinum •00088420x6-5 = -005747300 = -004789416 Dulong & Petit. 



Iron -00118203x6-5 = -007683195 = 006402662 DiilGng& Petit. 



Copper.. -00171821x6-3 = -011168363 = -009306970 Dulong & Petit. 



Tin -00217298x6.5 = -014124370 = -011770308 Lavoisier & Lapl. 



Zinc -00294200x6-3 = -019123000 — -015933833 Smeaton. 



Lead -00284836x6-5 = -018314340 = -015428616 Lavoisier& Lapl. 



Brass -00193000x6-5 = -012545000 = -010434166 Smeaton. 



Gold 00146606x6-5 = -009529390 = -007941158 Lavoisier & Lapl. 



Silver.... -00190974x6-5 = -012413310 = -010344424 Lavoisier & Lap!. 



Upon deducting from the amount of these several absolute 

 expansions the apparent expansions in the black-lead register, 

 we shall obtain the expansion of the latter from 62° to 212°, 

 as derived from the several metals. The results are com- 

 prised in the following Table. 



Table VII. 



Expansion of the Metal Bars. 



Platinum.... absolute •004'78 

 apparent ^00276 



Iron absolute •00640 



apparent -00508 



