136 REPORT — 1844. 



withdrawing the iinitii)g wire by means of a glass handle attached to its cen- 

 tral part. 



Insulator a. Insulator b. 



Electrometer B. Electrometer D. 



reb.3 67-5° 70° 



47-J 50 



27-^ 30 



New charge. 



77-5 80 



57-5 60 



37-5 40 



The window was now opened and a board was fitted into the frame (of the 

 sash), having two apertures of about 5 inches diameter, situated a little higher 

 than the caps. 



Insulator a. Insulator b. 



Time. Electrometer A. Electrometer C. 



Feb.6. 14h38m 20° 20° 



14-25 14 



9-5 6 



The apertures of the window-board were diminished to 2| inches diameter, 

 and the lamp of the insulator b raised a little. A double wick was used in it. 



Insulator a. Insulator*. 



Time. Electrometer A. Electrometer C. 



Feb.9. 14hl5m 205° 20° 



14 14 



5-5 5 



New charge. 



20 20 



5-5 5-5 



The board was removed and the window closed. Both the lamps were 

 used with double wicks and their chimneys attached to a lower board or shelf 

 (as in fig. 3), in order to prevent more effectually any hot air with steam 

 (arising from the combustion) from reaching the caps, <S:c. 



Insulator a. Insulator *. 

 Time. Electrometer A. Electrometer C. 

 Feb. 14. Uhlm 19° 19° 



10 11 



6 5 



The window was again opened and the board with the smaller holes used. 



Insulator a. Insulator*. 



Time. Electrometer A. Electrometer C. 



Feb. 15. lOhlSm 20° 20° 



6 5 



Electrometer B. Electrometer D. 



80 80 



60 60 



25 25 



10 10 



Here we have also a very fair approach to comparability. 



3. Comparison of three Insulators. 



The insulators a and b remaining as in experiment 2, and the window 

 being closed, a third insulator (c) was attached by its collar, <Src. (as usual) 

 to a round table placed near to the others, with its chimney-lamp, &c., but 

 no lower shelf wan used. The electrometer E used with C had been found to 

 accord very nearly with A and C. A fire burned in the stove of the room. 



