Presidential Address. By A. B. Michael. 103 
the sky for a good light when working by daylight. The zenith is 
often blue, and the best light is often found not very far from the 
lowest part of the sky visible ; but it is exactly in this position that 
we get the image. It would be convenient if the milled heads could 
revolve out of the way, and I think it might be done. 
Now a few words about some articles which, although not part of 
a Microscope, are often used with it. We are extremely careful to 
achromatise our substage condensers : why should we not do a little 
in the same direction for our stand-condensers ? The two cases are 
not altogether similar, and the latter is far less important ; but I 
fancy that something might advantageously be done more frequently 
than it is. Then there is the question of knives. No knives are 
manufactured for microscopical work ; the ordinary scalpels sold are 
utterly unsuited for microscopical purposes. The finest knives that one 
can buy are those made for oculists ; but even these are much too 
coarse for delicate microscopical work. It might be worth while for 
the makers of Microscopes to see if they cannot get some knives made 
fit to use with them. Then knives want sharpening. Good dissect- 
ing — and, to an even greater degree, good section-cutting — depends 
greatly upon the sharpness of the knife and the smoothness of its 
edge. Probably the best thing we have for sharpening is an Arkansas 
stone ; and something may be done by using soap instead of oil ; but 
might we not possibly manufacture something of even finer grain ? 
Of course, I am not alluding to finishing-strops. Finally there are 
lamps. These have received a good deal of attention, but still I fancy 
there is much room for improvement. A lamp otherwise well manu- 
factured, frequently — perhaps I might say usually — has a badly made 
and flimsy burner ; and it is desirable to be able to get the image of 
the flame without the image of the metalwork overlapping it when 
the lamp is some distance above the mirror. Sufficient care is not 
always taken to prevent the paraffin from sucking up by capillary 
attraction and spreading all over the outside of the reservoir, &c. ; 
and in lamps with metal chimneys, there should be some simple means 
of taking the chimney off while the lamp is alight without burning 
one’s fingers. The chimney should be left off until the lamp is re- 
lighted, which greatly diminishes the unpleasant smell otherwise 
arising upon lighting it. 
I propose to occupy what little time remains to me in giving you 
a very brief resume of some portions of the microscopical work which 
has occupied most of my time during the last three years. The re- 
sults were laid before the Linnean Society in April last, and have just 
appeared in their Transactions ; but, as the greater number of our 
Fellows here do not belong to the Linnean, and had not the oppor- 
tunity of hearing them there, they may take some little interest in 
doing so now ; particularly as, when last year I addressed you on the 
anatomy of the Acarina, I was obliged, in justice to the Linnean 
Society, to be wholly silent respecting that of the Bdellinae, which 
