216 Notices respecting New Books. 



iodine, if he did not wish to make a secret of it, he should have 

 written at the time a full and explicit paper on the subject, and 

 published it through the medium of some scientific society or 

 journal. In question of priority, it is not enough to have slated 

 that we have made the discovery of a new agent; we must 

 prove it by enabling others to test it and to apply its properties. 



It must be observed that bromide of iodine is a compound 

 very little known in chemistry, that its real proportions have 

 not yet been accurately established, that it is excessively diffi- 

 cult to form the mixture of the two elements in the proper 

 relation to each other, which gives the increase of sensitiveness 

 to the Daguerreotype plate, and that excess of one of the two 

 elements destroys that sensitiveness. Mr. Goddard should 

 liave stated these proportions, and the mode of applying the 

 coating on the plate. Bromide of iodine alone is not sufficient 

 in the preparation of the Daguerreotype plate ; its vapours 

 must be applied when the plate has already been coated with 

 pure iodine. This was an important feature in my discovery, 

 which rendered it at once most valuable to photographers. 



Nevertheless the name of Mr. Goddard should be honour- 

 ably mentioned in the history of the progress of photography; 

 not only for the discovery to which I have just alluded, but 

 also for having been one of the first in England who investi- 

 gated with zeal, enthusiasm, and scientific abilities, all the 

 phaenomena connected with this admirable invention. 

 I have the honour to be, Gentlemen, 



Your most obedient Servant, 

 London, Feb. 23. 1848. A. ClaUDET. 



XXXIII. Notices 7-especting New Books. 



A Description of Active and Extinct Volcanos, of Earthquakes, and of 

 Thermal Springs, ivith remarks on the cai/ses of these phenomena, 

 the character of their respective products, and their infiuence on the 

 past and present condition of the Globe. By C. Daubeny, M.D., 

 F.R.S. Second Edition, greatly enlarged. London : Simpkin, 

 Marshall and Co. 



THERE is no department of terrestrial physics (we speak not of 

 astronomy) which gives us a more exalted view of the grandeur 

 of Nature's operations, than the jjhsenomena of volcanos. 'i"he end- 

 less diversities of organic life, past and present, the marvels of che- 

 mistry, of optics, of crystallography, of acoustics, of electricity, and 

 the other sensible properties of matter, captivate the observer by their 

 beauty rather than by their sublimity. But in the volcano and its con- 

 comitants, the eruption, the lava-stream, the earthquake, the thermal 

 spring, we are allowed a glimpse into the very workshop of Nature ; 



