344 Proceedings of the Boyal Society 
6. He prepared grandly illustrated papers on the minuter forms of 
microscopic infusoria. 
7. Long before he adopted photography as a profession, and when 
very few persons in this country knew anything about it, he had 
become conversant with the then newly -born art in all its chemical, as 
well as its optical and mechanical details ; and he had prepared, with 
his own hands, special and instantaneous apparatus for applying it, 
on the one hand to record sun-spots as shown by a telescope ; and 
on the other hand, to picture microscopic images of his favourite 
forms of naviculse. 
How, how could any ordinary man occupy himself with all these 
arts and sciences, without being more or less shallow in some, and 
proving an undesirable leader or adviser in others of them ? 
It would be impossible ! and yet so conscientious a student and 
thorough a worker was E. W. Dallas, that he possessed skill and 
solid acquirements in them all. Without pretension or direct effort 
on his part, he was looked up to, as rather a notable authority, 
in all of them, by many persons who prosecuted only one or 
other single subject out of the many with which our late Fellow 
was conversant. 
At a meeting of the first Edinburgh Photographic Society, estab- 
lished by the late Sir David Brewster, when a novel kind of land- 
scape lens, invented by that very original genius the late Mr Sutton, 
was laid on the table, how the members in general were non-plussed ! 
It was a fluid-corrected, achromatic, globular lens with “butter- 
fly diaphragm” stop, and producing equal illumination and good 
definition over three times as wide an azimuthal angle as had ever 
before been obtained. Presently Elmslie W. Dallas entered the 
room and sat down in a quiet corner, when it was perfectly delight- 
ful to me (a non-professional looking on) to see how several of the best 
men in the room brought the lens to him, told him all their hopes, 
fears, and difficulties about it, and then hung expectant on his words 
as though they would prove infallible — and if he spoke at all, his 
words, on such a matter, might be accepted as infallible. For 
although, not only when questioned privately but also in public, 
he was often sufficiently discourseful, yet he could be silent when 
he chose ; and would not let popular applause, or personal requests, 
or hope of gain move him to give out a single opinion on any 
