Notices respecting New Books. 237 



hydrogen. The results of experiments made for very ex- 

 tended periods have shown me that unless the surface of the 

 zinc be at intervals kept clean mechanically by scouring, &c, 

 it soon ceases to protect, to any considerable amount, iron 

 or copper in foul sea-water : its surface gets gradually covered 

 with an impervious coating of microscopic crystals of calc 

 spar, which diminish, and at length destroy all reaction 

 upon it. 



No experiments on the mutual protection of metals in water 

 are worthy of dependence unless continued for a very long 

 time, by which reactions are brought into evidence which 

 would never have been perhaps suspected in experiments of 

 much more limited duration. 



Should you consider these observations suitable, I shall feel 

 obliged by their insertion in the Philosophical Magazine, and 

 am, Sir, your most obedient, 



94, Capel Street, Dublin, Robert Mallet; 



July 4, 1841. 



XXXIV. Notices respecting New Books, 



Elements of Chemistry, including the most recent discoveries and ap' 

 plications of the Science to Medicine and Pharmacy, and to the 

 Arts. By Robert Kane, M.D., M.R.I. A., Professor of Natural 

 Philosophy to the Royal Dublin Society ; Professor of Chemistry 

 to the Apothecaries' Hall of Ireland, &c. Part II. Dublin, 1841, 

 8vo, pp. 357 to 676, with 49 wood-cuts. 



HAVING in the preceding volume (S. 3. xviii.) of the Philosophical 

 Magazine, p. 304, given an analysis of the first part of Dr. Kane's 

 work, we now present our readers with the contents of the second part, 

 in a similar form : — 



Chapter X.— Of the Relations of Chemical Constitution to the 

 Molecular Structure of Bodies. 



Sect. I. Of the Atomic Theory (continued.) — Physical and chemical 

 atoms. Various orders of molecular groups. 



Sect. IF. Of Isomorphism. — Relation of constitution to form. Various 

 hypotheses on which the isomorphism of compound bodies has been 

 explained. Crystalline forms of the simple bodies. Isomorphous groups. 

 Principle of Plesiomorphism. Similarity of form does not prove necessary 

 similarity of chemical constitution. Principles of isomorphous replace- 

 ment. Of dimorphism and isomerism. 



Sect. III. Of Dimorphism and Isomerism, and of the Theory of Types. — 

 List of dimorphous bodies. Difference in structure of dimorphous bodies. 

 Change of physical characters indicating an approach to dimorphism. 

 Principle of isomerism. Connexion of dimorphism and isomerism. 

 Possible isomerism of the metals. Nature of compound radicals. Con- 

 stitution of organic bodies. Theory of organic types. Of actions by con- 

 tact. 



Sect. IV. Of Catalysis.— Oi catalysis and analysis. Catalytic effects of 

 heat. Catalytic effects ascribable to the communication of motion. 



