that every lighthouse, wherever situated, shall have a number--the
numbers not to run consecutively--and no two adjoining lights to have
the same numeral digits in the same place of figures. There would then
be no need for revolving or flashing lights, as the only thing to be
done would be to make each lighthouse repeat its own number all night
long, or whenever it was illuminated. This is to be 'accomplished by
enclosing the upper part of the glass cylinders of the argand burner
by a thin tube of tin or brass, which, when made to descend slowly
before the flame, and then allowed suddenly to start back, will cause
an occultation and reappearance of the light.' The number of
occultations denotes the number of the lighthouse. For instance,
suppose the Eddystone to be 243, the two is denoted by two hidings of
the light in quick succession; a short pause, and four hidings;
another short pause, and three hidings, followed by a longer pause;
after which the same process is repeated. It would not be easy to make
a mistake, for the numbers of the lighthouses nearest to the Eddystone
would be very different; and supposing that the boy sent aloft to
watch for the light were to report 253 instead of 243, without waiting
to correct his view, the captain, by turning to his book, would
perhaps find that No. 253 was in the Straits of Sunda, or some equally
remote situation, and would easily recognise the error. When we take
into account the number of vessels lost by mistaking one lighthouse
for another, the value of this proposal becomes apparent. Mr Babbage
shews, that bell-strokes might be employed to announce the number of a
beacon in foggy weather; and he believes that the time is not far
distant when buoys will also be indicated by a light. Now that
lighthouse dues are to be reduced one-half, we may hope to see
improvement in more ways than one.

This is but a small part of what promises more and more to become a