iieers, bankers, and bullion brokers, as well as to 

 experts in the Art of Assaying. The press has com- 

 mented upon it most favourably, and it has been 

 acknowledged to be by far the best work on the subject 

 suitable alike for the practical assayer and the general 

 inquirer. 



The second volume of the Series is written by Pro- 

 fessor Kimball, and deals with the physical properties 

 of Gases. He has taken into account all the most 

 recent works on ' the third state of matter,' including 

 Crooke's recent researches on ' radiant matter.' There 

 is a chapter also on Avogadro's law and the Kinetic 

 theory, which chemical as well as physical students will 

 read with interest. 



In the third volume Dr. Thurston treats, in a popular 

 way, on ' Heat as a Form of Energy ; ' and his book 

 will be found a capital introduction to the more 

 exhaustive works of Maxwell, Carnot, Tyndall, and 

 others. 



The fourth volume contains the only popular account 

 extant of the science of Geodesy, written by Professor 

 J. Howard Gore, of the Columbian University. 



The fifth volume, 'A Manual of Bacteriology/ by 

 Dr. A. B. Griffiths, is, as its title implies, a treatise on 

 the science of microbes, a knowledge of which is 

 essential to professional men engaged in checking the 

 spread of disease, and an advantage to all who value 

 health and sanitation. 



Other volumes will follow, written, like these, by 

 thoroughly competent writers in their own depart- 

 ments ; and each volume will be complete in itself. 



