PHOTOGEAPHY AND SOME OP ITS APPLICATIONS. 
631 
enormously magnified pictures of microscopic objects can be 
taken with great facihty. Those who were present at the late 
soiree of the Mcroscopical Society are aware to what extent 
Dr. Maddox has carried his labours in this field. There is not 
£nuch of special interest to be said concerning the mode in 
which these photographs are taken_, but there is a mode of 
exhibiting them which merits attention. With the oxyhy- 
drogen lantern_, gigantic views_, some feet in length_, may be 
obtained of objects whose natiual size is only to be measured 
by the thousandth of an inch. This is a fact of much 
importance to lecturers ; for by this means^ crude and ugly 
diagrams may be dispensed with^ and pictures of unquestion- 
able truthfulness substituted.* 
Of all the useful labour which photography has done for 
man there is_, however^ no one feat which she has accomplished 
more extraordinary than that by which she records the results 
of the philosopher's investigations. The story of Aladdin^’s 
lamp — that glorious tale of the ^‘’Arabian Nights^^ — which 
used so to excite our boyish emotions^ told us of no greater 
wonders than those of photography. The mysterious genius 
of the lamp^^ — that strange being whose powers were so unli- 
mited — was but the prototype of another spirit — actinic force — 
which promises even greater marvels than those achieved 
by its eastern predecessor. When we inform onr readers 
that the night-work at the Greenwich Observatory is now 
abolished^ and that through the long dreary hours when the 
human world is at rest_, photography is silently and steadily 
recording the phenomena of the physical universe^ om* Spirit 
of the Lamp ceases to be mythical. It would be impossible in 
the limited space at our disposal to enter upon a descrip- 
tion of the immense variety of contrivances employed in the 
Observatory^^ for recording the variations in the movement 
of the several instruments which such an institution possesses ; 
but we shall give an account of the means by which the move- 
ments of the magnetic needle are handed down to us by 
photography. The needle is so suspended that the apparatus 
suspending it carries a small concave mirror of long focus^ 
which moves uniformly with the needle itself. Placed oppo- 
site to this is a lamp (gas or photogen) ^ through a narrow 
sht in which a bright spot of light falls on the mirror. At 
a distance of about twelve feet from the latter there is a piece 
of mechanism_, comprised of a cylinder bearing photographic 
paper_, and attached to a strong time-piece_, so that it revolves 
* Some very good specimens of these photographs of microscopic objects 
for the lantern may he seen at Mr. Highley’s establishment, Green Street, 
Leicester Square. 
