May 25, 1905] 



NATURE 



Physical 



and 



Chemical 



Laboratories 



completely 



fitted up. 



HEELE'S FAMOUS SPECTROMETER. Price £10 10 O 



Including dense Hint glass prism, with micrometer movement, reading to i minute. Universally acknowledged to be the 



most efficient instrument on the market. 

 Also, smaller size, Price £6 nett, including two pri-ms, one being a hollow prism. As supplied to the Royal College of Science, 

 Dublin, University College, GowerSt., London County Council, St. Munchins College, Limerick, and many other leading Institutes. 



DEUIVERY FROM STOCK. 



PETER HEELE, 1X5 High Holtoorn, ^Rl.C 



MAKER OF PHYSICAL, ASTRONOMICAL, AND OTHER INSTRUMENTS. 



W. G. PYE & CO., '^GRANTA" WORKS, CAMBRIDGE. 





PHYSICAL, ELECTRICAL AND 

 PHYSIOLOGICAL 

 INSTRUMENT MAKERS. 



Best Quality Apparatus for 



Teaching and Research, at 



most moderate Prices. 



High Voltage Battery, consisting of 

 500 cells, giving at least looo volts. 

 As supplied to the National Physical 

 Laboratory, Cavendish Laboratory, 

 Cambridge, National Bureau of 

 Standards, Washington, U.S.A., etc. 



Price complete with regulating- switch, 



ammeter, charging and discharging 



connectors, in lock-up cabinet, 



J355 : O : O. 



Catalogues and Pamphlets free. 



