September 28, 1905] 



NA TURE 



IMPROVED APPARATUS 



for DEMONSTRATING 



WIRELESS TELEGRAPHY. 



Especially suitable for Colleges and Scientific Institutes. 



Full instructions witii diag 



HAItFC^y W. cox;, Utd., 



ACTUAL MAKERS of X-Ray. &c.. Apparatus to the Admiralty, 

 War Office, Colonial Office, Indian Government, &c., 



la ROSEBERY AVENUE, 4 15-21 LAYSTALL ST., LONDON, E.C, 



iLl-rsiKAil-M CATAl.o<;iTE(ini;lu.ling Inslruaions to li,-ainnf rs ) Post Fr^p. 



PURE 

 CHEMICALS 



KOR 



LABORATORIES 



AT CLOSEST PRICES. 



Write for List, and Special 

 Quotation for Quantities. . 



SOLE MAKER OF 



STRUTT'S RADIUM "CLOCKS." 



(i) For Lecture Table. 



(2) As Lantern Slide. 

 FuU particulars and prices on application. 



W. MARTINDALE, 



Manufacturing- and Analytical Chemist, 

 10 NEW CAVENDISH ST., LONDON, W. 



Physical 



and 



Chemical 



Laboratories 



completely 



fitted up. 



HEELE'S FAMOUS SPECTROMETER. Price £10 10 O 



Including dense flint glass prism, with /»/o/-0/Herec movement, reading to I minute. Universally acknowledged to Ije Ihe 



most eflicient instrument on the inarkel. 

 Also, smaller size. Price S6 nett, including two prism?, one being a hollow prism. As supplied to the Royal Collego of Science, 

 Dublin, University College, Gower St., London County Council, St. Munch in's College, Limerick, and many other leading Insiitutes. 



DELIVERY FROM STOCK. 



PETER HEELE, 1X5 Hi^K H:oll>or*n, W,C, 



MAKER OF PHYSICAL, ASTRONOMICAL, AND OTHER INSTRUMENTS. 



