45, COENHILL, B.C., AND 122, REGENT STREET, W., LONDON. 419 



c 



FIG. 2431. 



FIG. 2424. FIG. 2444. FIG. 2432. FIG. 2434. 



FIG. 2437. 



2420 Harris's Unit Jar Electrometer, with graduated slider, 



for charging Leyden jars, or batteries, with known 

 quantities of electricity (fig. 2420) .... 



2421 Saussure's Electroscope, for experiments on atmospheric 



electricity (fig. 2411*) ....... 



2422 Harris's Electro-Thermometer, for measuring the 



heating power of electricity 



2423 Kinnersley's Electrical Thermometer, a modification of 



Harris's instrument for exhibiting the transient 

 expansion of air by the passage of Electricity through 

 it (fig. 2423, page 426) 



2424 Calorometer, Hare's, or jointed insulated forceps, for 



conveniently supporting wires, through which it is 

 wished to pass an electric current, to ascertain the 

 heating power by the length of wire heated (fig. 2424) 



2425 Electrical Condenser, consisting of two brass plates, one 



supported on a glass insulating stem, the other rest- 

 ing upon a conducting stem jointed at the bottom 

 (fig. 2425) 



2426 Improved Electrical Condenser and Apparatus, for 



experiments upon disguised or paralysed electricity, 

 arranged to connect with a gold leaf electroscope 

 (fig. 2426) 



2427 Magic Picture, or Fulminating Pane, in frame, for 



giving slight shocks (fig. 2427) 



2428 Insulated Stools, for medical and other purposes, where 



it is required to insulate a body from the ground 



2329 Ditto, with Mahogany top (fig. 2429) see page 415 



2430 Insulated Adjusting Table Stand, with hollow Glass 

 support, best make (fig. 2430) see page 426 



Each, 

 s. d. 



7 



10 



1 1 



s. d. 



1 15 



150 



1 16 



100 



1 10 



18 



220 



10 6 



16 



1 10 



10 6 



2s 2 



