NATURE 



[February 27. 1919 



The BECK pSSU, BINOCULAR 



BECK BINOCULAR MICROSCOPE. 



No. 1031 P.S. 



(Patent) 



Not only an advance on 

 previous Binoculars, but 

 better than a Monocular 

 with all powers. 



Resolution equal to 

 thai of a Monocular. 



Equal illumination in 

 both eyes. 



Short tube length. 

 making Microscope 



compact. 



No special object- 

 glasses or eyepieces 

 required. 



Standard angle of con 

 vergencc. 



6. Stereoscopic vision. 



7. Binocular vision, 

 saving eyestrain and 

 giving better results 

 than Monocular vision 



8. Converted into a Mon- 

 ocular by a touch. 



Full descriptive Booklet and Price List on application. 



R. & J. BECK, Ltd., 68 CORNHILL, LONDON, E.C.3 



SLIDER RHEOSTATS 



require a well-designed contact 



HERE IT IS. 



CONTACTS OH WIR€ 



ISENTHAL & CO., LTD. 



(Department i), 



DENZIL WORKS, WILLESDEN, LONDON, N.W. 10. 



Contractors to the Admiralty, liar Office, India 

 Office, Colonial Office, PostmasUr-Ceneral, &c 



1^1 



m> 



One of the reasons for the great popularity of the Versalic ^ inch Oil Immersion 

 Objective is the number of kind recommendations by Versalic users in every 

 branch of science. 



Its long working distance, its immovable front lens, and the beautifully 

 clear image that it gives have made it a universal favourite. The definition 

 is always superb, even when deep eyepieces are used. 



Sole Manufacturers: — 



W. WATSON & SONS, Ltd., 313 High Holborn, London, W.C. 1. 



War Price £6 17 6 



Accurately Graduated Glass 



Laboratory Apparatus. 



CYLINDERS, 



FLASKS, 



PIPETTES, 



BURETTES, 



NITROMETERS, 



IVfa.de toy 



STANDLEY BELCHER & 



CARBON TUBES, etc. 

 MASON, LD„ 



Church Street, Birmingham, 



Graduating and Class Blowing I LUDGATE HILL. B'HAM. Pure Acid Works-HOOPER STREET, B'HAM. 



a Great Britain by R. Clay and Sons. Limited, at Brunswick Street. Stamford Street. S.E.l,and miblished bv Macmillan an 

 at St. Martin's Street, London, W.C 2, and Thb Macmillan ffy., 66 FJMh A"»nu#. New York.— Thursday. February 2; 



K1LLAN je»., 66 FiMh Attnuf, !■ 







