13 
of lighting. For this purpose nbt only should the current 
be regular in its action, but the distance between the carbon 
points must not alter, which necessitates the use of some 
arrangement for bringing them nearer together in propor- 
tion as they are consumed. Much ingenuity has been 
displayed by electricians in solving this problem, and the 
automatic contrivances invented by Staite,Duboscq, Foucault, 
Serrin, and others, leave little to be desired in regard to the 
steadiness of the light, when the regulators are in good 
order, and in the hands of intelligent operators. All auto- 
matic instruments, however, from the delicacy of their 
mechanism, are liable to derangement, and their action is 
not easily understood by persons not having a special 
knowledge of their construction. To obviate the objection 
to the use of such instruments by unskilled attendants, I 
devised, a few years since, a regulator for use on H.M/s ships 
of war, to be actuated by hand. In this arrangement the 
carbons are made to approach and separate from each 
other by means of a right and left handed screw connected 
with the carbon holders. Each of the screws, with its car- 
bon holder, can be actuated independently of the other, for 
the purpose of adjusting the points of the carbons to the 
proper focus of the optical apparatus used in connection 
with it. The regulator, with its carbon points, is placed in 
the focus of a dioptric lens, which parallelises the divergent 
rays of light into a single beam of great intensity. The 
lens with the regulator is pivoted horizontally and verti- 
cally on the top of a short iron column, fixed on a 
raised platform above the deck ; and the beam of light may 
be projected upon any distant object within its range. This 
special application of the electric light, however, as will be 
seen, requires the frequent adjustment of the carbons by 
the operator ; but as he is always required to be in attend- 
ance to manipulate the projector, no inconvenience is expe- 
rienced through the absence of the automatic arrangement. 
