clxxxiv 



NATURE 



[September -, 1905 



DEPREZ SIGNAL, 



SINGLE OR 

 DOUBLE. 



A style for writing 

 on smoked paper is |_ _ — 



attached to the arma- ■ 

 ture of an electro- Sl3iauaiiu5;ii).j.;.i.'.ijm» 

 magnet, and when the 

 magnet is excited the style 

 suffers a small displacement 

 of adjustable amount. The 

 apparatus is very small with 

 extremely light moving parts. 

 It is readily clipped to the 

 stem (10 mm. diameter or 

 under) of a simple stand, and 

 fine adjustment is ]irovided for 

 bringing the style up to the 

 paper. In the double form (as 

 illustrated) two styles with 

 independent electro-magnets 

 are mounted side by side. If 

 desired, one maybe connected 

 with a pendulum or tuning- 

 fork-interrupter to mark time 

 while the other registers the 

 events to be investigated. 



SINGLE DEPREZ SIGNAL, 



complete in box, £2 lOs. 



DOUBLE DEPREZ SIGNAL, 



complete in box, £3 XOs. 



THE CAMBRIDGE SCIENTIFIC 



INSTRUMENT COMPANY, LTD.. 



i-.i MnmiKi K. Ksa LA yi>. 



R. FRIEDLANDER & 



BERLIN, N.W.6. 



PUBLISHED ON .-VUGUST 24TH. 



ZOOLOGISGHER JAHRESBERIOHT 



Fiir 1904, red. v. Dr. PAUL MAYER, Neapel. 



In one Vol. Royal Svo. Price 24s. 

 (IRMTHOLnCV OF ICELAND. 



BEITRAG ZUR VOGELWELT ISLANDS. 



By B. HANTZSCH. Pg. 347, with 26 IIIus. & Map. Price 12s. 



DIE VOGEL DER PAL/EARKTISCHEN FAUNA. 



Part III. by E. HARTERT. In 10 parts at 4s. 

 CATALGCUS MAMMALIUM. By E. L. TROUESSART. 



(Juinquernale supplementum, 4 Parts. Price 44s. 



-- — -- .•.. — .. BEWAEE OF 



FEEBLE 

 IMITATION Is 



SOHN, 



£8. 



DO YOU WISH 

 TO BE 



UP TO DATE 



n Scientific Demonstrating ? 



d for our full descriptive pamphlet of 

 the Kershaw-Patenl Lantern 

 (Stroud and Rendalfs and 

 Kershaw Patents), made of 

 best seasoned mahogany. 

 French polished, lined with 

 isbestos and R' 



ith tw 

 c obje 



double 

 res, 90° 



■ X 16" 



ALL ACCEiSOfilES SUPPLIED. ARC LAMPS, RESISTANCES, 

 STANDS. &c. 



„i°^B A. KERSHAW, Dorring-ton St., Leeds. 



CONTRACTOR TO H.M.'s GOVERNMENT. 



CARL ZEISS, 

 JENA. 



BRANCHES- 

 LONDON 29 Margaret Street, Regent Street, W. 



Berlin. Frankfort oM. H.imburg. Vienna, St. Petersburg. 



PalmOS Cameras. 



Fitted with ZEISS LENSES. 



cm., and 3i-in. X4j-in. and 5-it 

 . for Stereo and Panorama. 



Sizes — 6x9 and 9X 

 Also 9X18 c 



SUITABLE FOR PLATES, PACK FILMS, AND 

 ROLL FILMS. 



Illustrated Cita/o^'tu. " F/i," Post Free 011 application. 



THE JUBILEE CATALOGUE 



ISSUED TO MARK THE 

 HFTY YEARS' EXISTENCE OF THE FIRM 



OF 



E. LEYBOLD'S NACHFOLGER, 



eOLOGNE, 



Contains on its more than 900 pages a complete 

 survey of the apparatus used for instruction in 

 Physics, as well as numerous practical instruc- 

 tions and about 3000 illustrations. 



NATURE says:— "The firm of Leybold Nachfolger 

 in Cologne has recently issued a very complete and 

 interesting catalogue of physical apparatus and 

 fittings sold by them The book starts with a history 

 of the instruments made in Cologne during the last 

 century. In its second section we find an account 

 of the construction and fittings of various chemical 

 and physical institutions. After this follows the cata- 

 logue proper, filling some 800 large pages, profusely 

 illustrated and admirably arranged. The book will be 

 most useful to the teacher." (No. 1846, Vol. 71.) 



THE CATALOGUE WILL BE FORWARDED TO SCHOOLS 

 AND INSTITUTES ON APPLICATION. 



