19 
incandescent lamps in use, and a million or two in England, if we 
include British steamships. The successful Incandescent Lamp 
is a filament of charcoal in a vacuum. This was at first 
prepared from cotton or strips of bamboo, but new is made from 
cellulose (gun cotton dissolved in naphtha), which is cut into 
strips. and attached to little platinum wires and then either 
baked in plumbago dust or (now more generally under Sawyer 
and Mann’s patent) flashed by electricity in hydro-carbon gas. 
The result of either of these methods is that the cellulose wholly 
disappears, and a solid thread of very superior charcoal is 
produced which will last for about 1,500 hours of light, and can 
be made of a size suitable for a tiny lamp not giving more light 
than a single candle up to the size suitable for a lamp equal to 
3,000 candles. Hlectrie power for lighting dwellings is now 
being supplied by large companies, an effective meter having 
been invented to shew the quantity used which is indicated by 
the deposit of metal caused by the passage of the electric current. 
MEANS OF OBTAINING LIGHT. 
Our early ancestors, like existing savage tribes, obtained light 
with considerable difficulty. Certain natives of Australia always 
carry the fire in a ball of grass, and seem hardly able to kindle it 
afresh. Other savages obtain light by rubbing two sticks, that 
is—either by revolving a hard stick against a soft one by hand, 
or with the bow string,—or by sawing one half of a bamboo 
across the other half bamboo. Both these methods are tedious and 
troublesome. Obtaining fire by striking two flints, or by striking a 
flint against a fire stone (iron pyrites) and catching the spark in 
dry moss or wood dust, was a great advance. And when steel 
became known, and there was added a slip of wood coated with 
sulphur which easily took light from the incandescent dust or 
tinder, nobody for thousands of years seemed to think anything 
better could be devised. It is true that fifty years ago, people 
had frequently to ride long distances to get a light when their 
tinder happened to be damp, a very common thing in Scotland 
and Ireland. All guns also were fired by flint and steel 
locks, indeed some millions of gun flints are still annually made 
at Brandon in Suffolk for export to savage tribes. About three 
hundred years ago, the Venetians invented a sort of umbrella- 
stand in which a dozen pieces of prepared rope were placed 
upright in a tray of gun powder, fired by a flint gun lock; thus 
instantaneously supplying each sailor with a means of firing his 
cannon. No chemical means of obtaining light appears to have 
been attempted till in 1805, Chancel, of Paris, brought out a bottle 
containing asbestos saturated with sulphuric acid into which a 
match coated with sulphur tipped with chlorate of potash was 
