488 SUMMARY OF CUERENT RESEARCHES RELATING TO 



convergent, the distance through which the interference can be dis- 

 tinguished decreases, and the precision of focusing increases. 



In the case of self-himinous objects, although the geometrical image 

 is still to be considered as an interference pattern, the effects outside of 

 the focal plane are greatly modified by the absence of definite phase- 

 relations between the waves emanating from various points. 



Gleichen, a. — Leitfaden der praktischen Optik. 



Leipzig : S. Hirzel, 1906, viii. and 221 pp. 



(6) Miscellaneous. 



Textile Fibres.* — The well-known work of J. Merritt Matthews 

 on the physical, microscopical, and chemical properties of textile fibres 

 has recently passed into a second edition. To the microscopist the 

 microchemical reactions and microscopical appearances and properties 

 of fibres are necessarily the more important topics. These features are 

 prominent, are treated of very fully, and are amply illustrated, mostly 

 from original preparations of the author. The micro-analytical tables, 

 which form a section of the chapter on the qualitative analysis of textile 

 fibres, will be found very useful, not only to the practical operator, but 

 to the amateur. 



On the whole the work is fairly well balanced, though cotton receives 

 considerable attention, over one hundred pages being devoted to it. In 

 addition to the text proper, which treats of wool and hair fibres, shoddy, 

 silk, cotton, linen, and other vegetable fibres, are four appendices. 

 These deal with the microscopic analysis of fibres, a machine for 

 determining the strength of fibres, commercial varieties of American 

 cotton, and the bibliography of textile fibres. The volume is well got 

 up, and the illustrations numerous and clear. 



Quekett Microscopical Club. — The 440th Ordinary Meeting of the 

 Club was held on May 17, the President, Dr. E. J. Spitta, F.E.A.S., 

 F.R.M.S., in the chair. ' 



A paper by Mr. F. Chapman, A.L.S., F.R.M.S., on " Some Littoral 

 Gatherings of Foraminifera from Victoria, Australia," was read by 

 Mr. A. Earland. The author gives an account of the literature on 

 Victorian Foraminifera, and describes the geology of the localities from 

 which gatherings were obtained. A detailed list of some 10;^ species is 

 attached. Mr. Earland prefaced his resume of the paper with some 

 hints on the usual methods of collecting, and some very interesting 

 remarks on tbe life-history of Foraminifera. 



At the 441st Ordinary Meeting, held on June 21, the President in 

 the chair, Mr. C. F. Rousselet, F.R.M.S., read a paper " On Brachionus 

 sericus sp. n., and a new variety of Brachionus quadratus, and remarks 

 on Brachionus rubens Ehrenberg." The new species was first met with 

 in 1895 at Totteridge, and has since been obtained sparingly at other 

 places near London, and also from Dundee and Exeter. In general 

 appearance it resembles B. urceoJaris. 



* New York : John Wilev and Sons ; London : Chapman and Hall, 1907, 

 480 pp., 126 figs. 



