THE AMERICAN 



MONTHLY 



MICROSCOPICAL JOURNAL 



Vol. I. 



I^EW York, October, 1880. 



No. 10. 



A Warm-stage for 

 Microscope. 



the 



BY PKOFESSOE E. H. BARTLEY. 



Having occasion to use a warm- 

 stage during the winter of 1878-9, 

 and finding some difficulty in main- 

 taining a uniform temperature by 

 any of tlie simple devices with 

 which I am acquainted, I have 

 constructed and used the apparatus 

 illustrated 

 the 



m 



ac- 



FlG 



company- 

 ing sketch ; 

 which is so 

 easy of con- 

 struction 

 and an- 

 swers the 

 purpose so 

 well, that 



I have 

 thought it 



worth 

 while to re- 

 commend it to others through the 

 Journal. 



It consists of a vessel of water 

 (A), which is supported on a tripod 

 or a lamp-stand, and capable of 

 being raised and lowered at will ; 

 the water in it is kept boiling when 

 in use, by the lamp C. 



A glass tube {a a) about 6™'"- in 

 diameter and about 30^^™- long, is 

 bent upon itself at h so as to bring 

 the two limbs parallel and within 

 about 1.5*^™- of one another. One 

 of the ends of this tube is then 

 drawn o£f to a fine point, as shown 



at c, and is bent at an angle of 45° 

 at a distance of S""'- from this end- 

 The other limb of this tube is con- 

 nected with the siphon tube d, by 

 the rubber tube/*. D is the stage of 

 the microscope ; and e, e, are two 

 pieces of cork which serve as sup- 

 ports for the tube a a, and as stops 

 for the slide, and which may be 

 cemented to the stage by mucilage, 

 to make the apparatus more steady. 



I have 

 sometimes 

 replaced 

 these corks 

 by strips of 

 sheet tin or 

 brass, so 

 bent as to 

 serve the 

 same pur- 

 pose. The 

 tube a a is 

 placed in 

 the usual 

 position of 

 the slide upon the stage, and the 

 slide is placed upon it ; the light 

 passes between the two limbs of the 

 tube. The vessel B receives the 

 water discharged at c. As long as the 

 water in A is kept at 100° C., and 

 a constant relation is maintained be- 

 tween the height of the water in this 

 vessel and the stage, the temperature 

 of the slide will remain constant as 

 long as the water flows. By rais- 

 ing or lowering A, the velocity 

 of the current of water may be in- 

 creased or diminished, and the tem- 

 perature of the slide is controlled. 



