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PHOTOGEAPHY AN AID TO ASTEONOMY. 
Presidential Address by S. S. Hough, M.A., F.E.S. 
(Eead April 19, 1911.) 
The reports you have just received relate to the administrative aspects 
of the work of our Society during the year, and no more fitting subject 
could be found for an address from the Chair than a similar summary 
of the annual scientific output. Unfortunately, if such a duty were 
thrown on your president, I fear that with such a vast range of subjects 
to review, as indicated even by the titles alone of the papers with which 
we have had to deal, the task would be overwhelming, and I have felt it 
necessary to adopt the alternative course of limiting my attention to a 
branch of scientific investigation in which I could but modestly hope that 
my own experiences w^ould enable me to speak with some pretentions to 
authority. 
In my address last year I endeavoured to put before you some of the 
problems which confronted the astronomer and to illustrate the reasons 
why the most refined methods of physical measurement available were 
necessary in order to secure data for the solution of such problems 
To-day I propose to deal rather with the methods in use and the progress 
which has been and is being made in securing the necessary data for 
discussion, and in particular to sketch to you the advances which have 
been rendered possible through the introduction of photography as an 
aid. 
Now-a-days when portable hand-cameras are accessible to every one, 
when photographs can be taken by the mere expedient of pressing a 
button, leaving the manufacturers who supply the material to "do all the 
rest" at a trifling cost, or when even the processes of development can 
be performed by an inexperienced operator without the aid of any more 
elaborate equipment than a supply of fresh water, one is apt to forget 
how recent is the development of photography, not merely as a science or 
art in itself, but still more as a useful adjunct to almost every other 
branch of scientific investigation. 
To appreciate the uses of photography try and imagine if you can 
