ZOOLOGY AND BOTANY, MICROSCOPY, KTC. 245 



sensibly the facility of the first class. But in cases where such proficiency 

 is not acquired, it is difficult to propose means of avoiding eye-fatigue. 

 Perhaps the best means is to raise the level of the drawing-paper until 

 a position requiring a minimum eye-accommodation is reached. This, 

 however, naturally has an inconvenient influence on the size of the 

 drawing obtainable. Another mode is the employment of certain lenses, 

 but has the disadvantage of being complicated. 



The study of the subject has suggested to the author that the camera 

 lucida might be used for making- a reduced drawing of a relatively large 

 object. He fully describes his method, which essentially amounts to a 

 reversal of the usual process. 



PuLFBiCH, C. — Stereoskopisches Sehen und Messen. 



[This is mainly a reprint of the article " The Stereoscope," contributed by 

 the author to the EncyclopEedia Britanuica, and is enriched by a full 

 bibliography of all works relating to the subject published during the last 

 eleven to twelve years. Jena : Fischer (1911) 40 pp. (17 figs.). 



(6) Miscellaneous. 



Coscinodiscus asteromphalus. — At the meeting of the Quekett 

 Microscopical Club on January 23, li)12, E. M. Nelson showed a photo- 

 micrograph of the eye-spot of Coscinodiscus asteromphalus, Maryland 

 deposit, styrax mount, x 3000. There was a fracture passing through 

 the cap ; this fracture proves the presence of a membrane covering the 

 eye-spot. 



Quekett Microscopical Club.— The •i78th Ordinary Meeting of the 

 Club was held on January 23, 1912, the President, Professor E. A. 

 Minchin, M.A., F.R.S., in the chair. Mr. James Burton read some 

 " Notes on Algaj collected in 1911." He had to record several instances 

 of " Breaking of the Meres " — June 24, at Totteridge, due to an unidenti- 

 fied species of Anahmia ; August 9, at Hadley, the same organism was 

 found. August 8, at Kew, in the pond near the palm house, the water 

 was suffused at all depths with Aphanizomenon flos-aquae. August 31, 

 Welsh Harp reservoir, due to MicrocijsHs marginata. Mr. A. Earland 

 exhibited in the lantern a number of photomicrographs of Foraminifera 

 prepared to illustrate the principal types of rhizopod shell structure. 



The Annual General Meeting of the Club was held on February 27 . The 

 President delivered the Annual Address, dealing with " Speculations with 

 regard to the Simplest Forms of Life and their Origin on the Earth." 



Professor A. Dendy, D.Sc, F.R.S., F.L.S., was elected President for 

 the ensuing session. 



Vernier Micrometer. — At the Meeting of the Optical Society, 

 October 26, 1911, J. W. Gordon demonstrated a new form of Vernier 

 Micrometer. The scale consists of black lines on a white ground, with 

 a thick black line at right angles to the divisions ; this is viewed through 

 a coarse transmission diffraction grating, by rotating which three scale 

 images are formed which move relatively to one another in the direction 

 of the length of the scale. These divisions are easily seen where they 

 lie over the thick black line. By suitable marks arranged on the cir- 

 cumference of a circle printed with the scale, the amount of rotation of 

 the diffraction grating is read without removing one's eye from the scale.. 



April 17th, 1912 s 



