MAR 14 1911 



A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



" To the solid ground 

 Of Nature trusts the mind which builds for aye." — Wordsworth. 



No. 2261, Vol. 90] 



THURSDAY, FEBRUARY 27. 191 3 



[Price Sixpence 



the General Post Office.) 



[All Rights Reserved. 



BAUNCES&WEICHTS 



J. GRIFFIN ($••> 



John 



Physical Apparatus 



MAKERS OF 



THE GRAY-BURNSIDE 



MOTOR GYROSTAT 



for demonslratinc; all the properties and 

 practical applications of the f;yrost;it. 



GYROST ATIC PEN DULUM 

 GRAY'S GYROSTATIC MODELS 



As demonstrated at the Phy.5ical Society. 

 PRICES O.V APPLICATTOir. 



Kemble St. KINGSWAY London, W.C. 



REYNOLDS & BRANSON, Ltd., 



Manufacturers of Chemical and 

 Physical Apparatus. 



GRAND PRIX AWARD. TURIN. 19H. 



THE " RYSTOS " ELECTROSCOPE. 



This Electroscope, with paraffin 

 insulator, remains charged for at least 

 a day, and has been used with the 

 greatest satisfaction in many secondary 

 schools for the last ten years. A 

 customer states that the batch of two 

 dozen, obtained two years previously, 

 has remained in efficient condition 

 during that time. 



(a) Price with attachment for two Wires and top re-1 g, ^^^^ 



movable for cleaning the glasses / ' 



(6) Ditto, with two glass tubes for showing the leak- \ g,g ^^^^ 



age caused by a radio-active gas.. .. ... / ' 



(c) Ditto, with transparent scale, lecturer's pattern, "l 



for projection of image of gold leaf and scale • T/6 each. 



by means of a lantern j 



The 



"Seathwaite" 



Rain Gauge ^^ 



has a 5-inch 

 diameter funnel, 

 and a capacity of 

 30 inches of rain. 

 It is constructed to 

 prevent evapora- 

 tion and freezing. 

 The gauge for 

 outlying districts. 



NEGRETTI 

 & ZAMBRA, 



Holborn Viaduct, 



London, E.G. 

 45 Cornhill, E.G. 

 122 Regent St., W. 



