890 SUMMARY OF CUREENT RESEARCHES RELATING TO 



Heueck, H. Van. — Eclairage artiftciel; Eclairage electrique par incandescence. 



(Artificial illumination : Incandescent electrical illumination.) [Supra, p. 864.] 



Synopsis des Diatome'es de Belgique. Texte. 1885, pp. 219-22 (3 figs.). 



Cf. Jmrn. Soo. Arts, XXXIII. (1885) p. 1005. 



HiPPiSLEY, J . — A pocket field Microscope. 



["Magnifying 100 diameters, useful in the search for infusoria, &c., and 



■which may be constructed, lens and all, in a few minutes. 

 Bend a slip of thin metal 5 in. or 6 in. long and 1/2 in. wide into the form 

 of the letter V, make two circular holes 1/10 in., one in each arm, opposite 

 each other, so that when the arms are sprung together by pressure the 

 holes shall meet exactly. Place a drop of water in one hole, taking care 

 not to wet more than its interior circumference. The water will assume 

 the form of a perfect double convex lens, of focal length varying from 1/8 

 to 1/10 in. according to the quantity of water introduced. Such lens, 

 though by evaporation its focal length is gradually increased, maintains 

 its efficiency for a time quite sufficient for the examination of a drop of 

 water or other substance in the opposite hole. The end of one arm of the 

 V is bent inward so as to form a " stop," which when they are pressed 

 towards eacli other to eifect the focal adjustment, prevents a contact which 

 would destroy the lenticular form. The definition of these water-lenses 

 is excellent, and their magnifying power is from 80 to 100 diameters, 

 according to the quantity of water in the lenticular drop."] 



Engl. Mech., XLI. (1885) p. 502. 

 „ „ Microscopic. 



[It is very easy to make glass globules for microscopic use of ordinary 

 glass. The difficulty is in using them as Microscopes. Besides the 

 instrumental difficulty of focal adjustment for such small lenses, the 

 light of so small a pencil of rays is quite inadequate, except with 

 " violent " illumination. " But lenses by melting glass may be made to 

 much better purpose of more useful focal lengths — not globular — 

 but double-convex lenses, in the following manner, which, I believe, is 

 new, or was so when I first made them, say 30 or 40 years ago. Take a 

 bit of fine binding wire, iron (not brass or copper), make, by twisting it 

 round a taper wire for mandrel, a nicely circular loop; flatten it so that 

 the loop is all in one true plane. The loop may vary in diameter from 

 any desired smallness up to 1/4 in. (which is nearly the largest size my 

 glass-melting apparatus will conveniently manage). Place a square 

 piece of glass — thicker or thinner, according as it is desired to have a 

 lens of more or less convexity, but large enough to completely cover the 

 loop. Then, holding it in a suitable blowpipe flame (which should be a 

 vertical, not a horizontal one), the glass assumes in melting a doubly- 

 convex lenticular form. A form, moreover, in which the spherical 

 aberration of a globule tends to be corrected, and a larger proportion of 

 the field is flatter than it is with an ordinary double-convex lens." " Such 

 lenses are made in a few minutes, and perform most admirably when a 

 suitable instrumental apparatus is used."] 



Engl. Mech., XLI. (1885) pp. 540-1. 

 HiTOHCocK, R. — Optical arrangements for Photo-micrography and remarks 

 on Magnification. IPost.'] Amer. Mon. Micr. Journ., VI. (1885) pp. 168-70. 

 [Hitchcock, E.] — The Postal Club. 



[Comments on its position.] Amer. Mon. Micr. Journ., VI. (1885) pp. 134-5. 

 „ „ — Testing Objectives. 



[Kecommendation of the Abbe test-plate.] 



Amer. Mm. Micr. Journ., VI. (1885) pp. 177-8. 

 International Inventions Exhibition. XII. Philosophical lustriiments and 

 Apparatus. 



[Includes Microscopes and Apparatus.] 



Engl. Mech., XLI. (1885) pp. 444-5. 

 James, F. L. — American v. Foreign Microscopes. 



The Microscope, V. (1885) pp. 164-5, from the National Druggist. 

 Klein, C. — [Horizontales Erhitzungsmikroskop.] (Horizontal heating Micro- 

 scope.) \_Post.'\ Nachr. K. Gescll. Wiss. Gottingen, 1884, pp. 133-4. 



