310 The Microscope. 



densing lens. The strong air blast is carried by very simple 

 means around the oil reservoir to the base of the flame, which 

 burns with an intensity that to tlie naked eye is almost painful, 

 and with a pure and steady white light without a chimney, as 

 did its prototype, the Hitchcock contrivance. 



But the feature that at once commends Mr. Taylor's lamp to 

 the microscopist is the manner of regulating the draught and 

 the consequent intensity of tlie flame. This is accomplished by 

 a rotating diaphi'agm on the upper surfaee of the vessel that 

 encloses the machinery. By rotating this diaphragm, and of 

 course thereby opening or closing the aperture that admits the 

 air to the fan, the flame can be made a smoky and disgusting 

 thing, or a small, stead}'^ blaze, whose fierceness is painful even 

 to the trained eye of the microscopist accustomed to all kinds 

 of diatomaniac, not to say diabolical, illumination. With this 

 white, fierce flame, regulated so that its tip is just above the cap 

 of the burner, the etiect on the lenses used and on the Diatoms 

 examined is remarkable. With the highest power of objectives 

 and eye-pieces there is a superabundance of light, of a quality 

 that seems to clutch the Diatom with a peculiar force, that 

 appears to compel it to give up its striae and beads, with a 

 sharpness and a brilliancy that at the first view astonishes as a 

 revelation. Objectives that have done well before do better 

 now ; those that previously did not entirely well now act in a 

 pleasing way. 



With it a balsam-mounted Surirella can be resolved into beads 

 by a dry 1/5 with an angle of 135°. A balsam-mounted Amphi- 

 pleura, to the proper objective, reveals its longitudinal striae. 

 Nothing more need be said in this connection. The diatomist 

 now knows it all. 



Mr. Taylor's lamp is superior to the Hitchcock invention, 

 meritorious as that was in several particulars. It is more satis- 

 factory, because it can be more easilj- manipulated by a change 

 of position. The Hitchcock lamp was immovably fixed at a 

 certain height ; Mr. Taylor's diaphragm lamp can be raised or 

 lowered to suit the necessities of the case. It can also be 

 arranged to carry a bull's-eye condensing lens, although, for the 

 study of Diatom markings, that seems scarcely needed ; there is 

 plenty of light, more indeed than the microscopist well knows 

 what to do with ; and as for its brilliancy and intensity, they 

 are indescribable. But the crowning feature is the diaphragm, 



