ADDRESS. 



The previous editions of this General Catalogue having been out of print 

 for some time, I have now great pleasure in presenting this new and extended 

 impression. 



Had my object been the mere enumeration of the names and prices of 

 instruments, etc., the present edition would have been completed long since ; 

 but my desire was to unite with these a brief description of many of them, 

 including not only those of recent design, but also of others for which 

 explanations are often required. 



Amongst the new arrangements, I may mention the Deep Sea Thermo- 

 meter, with which the real temperature of the sea at any depth has at length 

 been determined ; the Pocket Standard Barometer, by means of which the 

 highest mountains or deepest shafts can be measured accurately ; the ex- 

 tremely portable Traveller's Transit Theodolite, Pocket Altazimuth, Pocket 

 Spirometer, and various important arrangements of Solar Badiation Apparatus, 

 Anemometers, etc. 



To self-registering instruments much of my attention is constantly given, 

 and several of them are now described for which I was honoured with the 

 only Prize Medal awarded to this class of instruments at the Great Exhibition 

 of 1862, as well as the much extended patronage of the leading Governments 

 and Observatories of the world, as shown on the title page. 



For clinical, general medical and physical investigations of temperature, 

 my arrangement of Self-registering Thermometers is now used exclusively, and 

 many instruments of my design for these purposes are now also regarded 

 as indispensable. 



