ELECTRIC DISCHARGE WITH THE CHLORIDE OP SILVER BATTERY. 
217 
cooled, the vacuum becoming better, seven, six, and so on to two in an inch 
were produced ; lastly, before the current ceased to pass, the strata rapidly 
widened out, flowing towards the 'positive. 
Tube 9, Hydrogen. 
223. — This is a tube with a diaphragm of glass having a hole in it 0’25 inch diameter, 
the length between the terminals being 1 1 inches ; it also has a potash 
chamber for the complete absorption of moisture, 9, fig. 37 ; with 2160 cells, 
the potash chamber having been previously heated, about three strata were 
produced in the compartment near the positive ; as the chamber cooled and 
the vacuum became more perfect, six strata formed in this compartment, 
completely filling it, and one after the other appeared to squeeze through the 
small hole in the diaphragm into the negative compartment, where two 
strata formed, each double, like those in fig. 3, Plate 16. 
Tube 116. 
224. — This is one of the so-called induction tubes, like, in some respects, that shown 
in 19, fig. 37 ; it consists, however, of three chambers, the distance between the 
terminals being 37 inches. It is composed of a large central tube 18 '5 inches 
long, 2 '2 5 inches diameter, terminating at each end in a bulb 2'5 inches in 
diameter, and containing carbonic acid. Enclosed in these bulbs are two 
smaller bulbs 2'125 inches in diameter, connected each with a spheroidal bulb, 
the major axis of which is 3 ‘375, and the minor 2 '5 inches ; these contain 
nitrogen. In these spheroids the terminals are placed, so that each is 
enclosed in a separate chamber (see Plate 18, fig. 5). On connecting this 
tube with 6960 cells a flash is perceived in the several compartments of the 
tubes ; on reversing the current another flash, but no continuous illumination 
as with the induction coil. As in an induction coil there is a series of 
rapid reversals of current, it is evident that it illuminates induction tubes 
by an alternate charging up and discharge of the leyden jars formed by the 
contained bulbs, on each side of which is residual gas, which acts as the 
carrier of electricity. By rapidly reversing the current of the battery by 
means of the key, figs. 2 and 3, page 59, Part I., the tube becomes 
illuminated, but not so well as with an induction coil. On, however, 
employing the rapid commutator shown in fig. 8, Part I., which alternates 
the current 352 times or less in a second, a most splendid illumination of 
the tube takes place, producing an appearance shown in fig. 5, Plate 18, 
copied partly from a photograph obtained when 6960 cells were used and 
with about 150 reversals of current in a second. The two spheroidal 
chambers communicating with the enclosed globes became illuminated 
MDCCCLXXVIII. 2 F 
