November 19, 19 14] 



NATURE 



3^5 



of artificial irons and steels, and his residence at 

 Sheffield enabled him to obtain the necessary 

 materals for a research, which not only resulted 

 in important discoveries by himself, but laid the 

 foundation of the science of microscopic metallo- 

 g'raphy, which has made such important advances 

 in recent years. 



Our illustrations are taken from the catalogue 

 of Messrs. James Swift and Son, who in this 

 country have been among the foremost in meet- 



Cooke 

 an ap- 



FiG. 1. — Swift's "Survey" Petrological Microscope. 

 A, Rotating analysrr working over ocular; B, 

 slot for quartz wedge or other compensator ; 

 C, divided circle worki g in c ■i.ja..ciion with 

 analyser a ; d slot through ocular (or micro- 

 meter, eic. ; E, slide ■ arrying upper Bertrand 

 lens which can be f cussed and pushed out of 

 theop'ic axi- when not required ; F, analyser 

 in body, instantly removable from optic axis ; 

 G, slot fi.r quariz wedg--, etc., when working 

 with analyxr f; h, centring n-.>epiece; j, 

 achromatic convergent system ; K, iris dia- 

 phragm ; L, loop for insta ily removing top 

 hemisp lerical 1. ns oi conden.-er ; M, swing-out 

 rotating cell for stops, compensators, etc.: 

 N, centring S' rews to convergent system ; 

 o, focussii g adjusiment for convergent system ; 

 P, polariser mounted on independent swing-out 

 arm. 



ing the often difficult requirements of scientific 

 men, by carrying out their suggestions with great 

 practical knovfledge and skill. J. ^V. J. 



DR. M. C. COOKE. 



BOTANISTS will learn with regret of the death 

 of the veteran mycologist. Dr. M. C. Cooke, 

 at Southsea on November 12. Mordecai Cubitt 

 Cooke was born at Horning, Norfolk, on July 12, 

 1825. His early education was scanty, but he 

 received help from his uncle, who instructed him 



NO. 2351, VOL. 94] 



in botany as well as in mathematics and lan- 

 guages. Some years later he became a lawyer's 

 clerk, and afterwards a teacher under the old 

 National School system, the economic value of 

 food-plants being one of his teaching subjects. 

 This led to his preparation of a catalogue for the 

 Indian Department of the Exhibition of 1862, and 

 eventually to work at the India Museum. Here 

 he spent much time studying the lower crypto- 

 gams, especially fungi, on which he soon became a 



leading authority. 



In 1880 

 obtained 



pointment in the 

 Herbarium of the 

 Royal Botanic Gar- 

 dens, Kew, being 

 placed in charge of 

 the Thallophyta, a 

 post which he con- 

 tinued to hold until 

 he retired at the 

 age of sixty-five. 

 Whilst at Kew he 

 completely re-ar- 

 ranged the my co- 

 logical collections, 

 and incorporated 

 the large and valu- 

 able herbarium of 

 the Rev. M. J. Ber- 

 keley, and later on 

 his own extensive 

 collections, which 

 have been estimated 

 to number 46,000 

 specimens. He also 

 dealt with material 

 coming in from 

 abroad, from which 



Fig. 2. — Swift's "Improved Dick" Petrological Microscope (Khartum Jjg described and 



model)i A, Analy^r mounted a 'ove ocular and gcare I to rotate c. A 



simultaneously wiih the polanser ; b, cross-webbed cular;c, slot UgUrCd many nev\ 



througT ocular f .r wcdgcs, micromeier, etc. ; D, lens 'or "-eading crvppipc D U r i n Sf 



circle and vernier ; E, divided circle reading by vernier to 5' ; " _ * • j l 



F, slide bearii g Bertrand lens (this lens is provided wuh a aia- this period he waS 



pliragm of apertures :!nd can be focussed and pushed out of the 5,c„:oj-f.|J |n his 



optic axis when not required); g, sliJe bearing lower Bertrand aSSlSieU 111 II 1 s 



lens, Klein's qiiar z plate and a elearap»-rture (this lowrr Bertrand private WOrk by 



lens shows a much larger interference figure than the upi»cr one, C, p. r a- (^ 



filling as it • o-s the entire field of tbe ocular); H, txi aanal>ser iVlr. Li e O r g C 



mounted in body (this analyser is generally used for phoiomico- MaSSCe who af ter- 

 graph>) ; J, tine adjusiment by diffeiential screw which by means ' A A 



of a vernit-r reads to ooooj mm. ; K. aplanatic oil immers on con- W a r d S SUCCeeueu 



denser, n.a. 140; L, ap anatic dry condenser, n.a. fo; M, iris UJm Jn liic HiifiP*; in 



diaphragm below which is a rotating swing-out cell for stops, "^'" '" '"^ uuiica m 



CO 1 pensators, etc. ; N, screws to centre coiideu>ers; o, polaii-ser the CryptOgamiC 



mounted on an independei.t swing-out arm ; p, milled head for -p^ «-monl- 



focu,sing condensers. Jjeparimcni. 



Cooke stands out 

 as a great systematic mycologist, and as a popu- 

 lariser of his science. His first important work — 

 "Handbook of British Fungi" — (1871) is a 

 classic, which to this day demands a good price. 

 The most celebrated is " Illustrations of British 

 Fungi." These eight volumes, containing 1200 

 plates of British Agaricaceae, are a stand-by of all 

 British mycologists, and the fact that they are 

 still the subject of scrutiny and criticism by 

 eminent continental botanists only testifies to their 

 importance in mycological literature. For twenty 

 vears Cooke edited Grevillea, a journal devoted to 



