45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 415 



FIG. 2394. 



FIG. 2392. 



3392 



40 



. d. 







Armstrong's Hydro -electric Machine (fig. 2392) 



This apparatus consists of a very strong boiler, constructed to sustain great pressure, for evolving 

 Electricity by the friction of water and steam against other substances. It is fitted with safety valve, 

 water gauge, condensing tubes, jets, collecting and discharging rods, &c. The boiler is heated by a coke or 

 charcoal fire, and supported on insulating glass legs with rolling castors. 



2393 Leyden Jars (fig. 2393)- 



Contents . J-pint. i-pint. 1-pint. 2-pints. 4-pints. 



Price . 2s. 6d. 3s. 6d. 6s. 8s. 6d. 15s. 



2394 Electrical Batteries, consisting of 4, 6, 9, 12, or more Leyden jars, mounted 



in frames or cases, with brass conducting rods and balls (fig. 2394) 



2 10s. ; 3 3s. 6 6 10 10 



2395 Medical Leyden Jars, mounted with Lane's Discharging Electrometer, to 



regulate the intensity of the shock given to a patient (fig. 2395) 



12 6 18 



3396 Leyden Jars, mounted, to show that the charge is not in the coatings, as 

 those with which it is charged can be removed, and others put in their 

 place, the glass retaining the electricity (fig. 2396) . . 16 6 



FIG. 2388. 



FIG. 2427. FIG. 2396. 



FIG. 2389. 



