274 ANNUAL OF SCIENTIFIC DISCOVERY. 



tion with the new facts which M. H. St. Claire Deville has lately published, 

 respecting the graphitic form of Silicon, Boron, c., in which a similarity 

 of conditions of production is essential to the effect being obtained. In 

 geological theory, the formation of anthracitic carbon in one case, and of 

 graphite, with the gradations back to anthracite, in another, has hardly been 

 explained ; but if we are allowed to take the allotropic state of carbon as a 

 distinctive character of that carbon, which has been sublimed, through the 

 agency of its own, or more likely a foreign vapor, then the occurrence of 

 these forms of carbon ceases to be anomalous, and accords with the circum- 

 stances under which many rocks have been produced. Graphite, graphitic 

 carbon, graphitic oxide of iron, and, in general, sublimates composed of 

 vesicular forms presenting lamina?, under this view become a class of bodies 

 which owe their forms to the transporting power of vapors in motion. 



" Another point observed in the decomposition of defiant gas deserves 

 notice. It is stated in most treatises on chemistry, and adopted as a matter 

 of belief in the gas manufacture, that olcfiant gas, when heated, deposits 

 two of its four proportions of carbon, and, without change of volume, be- 

 comes marsh gas. It is barely possible, as an accidental circumstance, this 

 proportion of carbon might be deposited, but it would take place, not as an 

 experimental, but as a chance result. When olefiant gas is passed through 

 ignited quartz, glass, or iron-turnings, it deposits carbon, which has no defi- 

 nite relation to the composition of the gas, a mixed gas being left, containing 

 olefiant marsh gas and hydrogen. If the gas is rcpassed, the carbon may 

 be nearly all abstracted, the marsh gas suffering decomposition. 



" The conditions of olefiant ga-s heated in the products of coal decompo- 

 sition are not such as to lead to a breaking up of its carbon arrangement, for 

 there are many reasons for tbe statement, that this bicarburct is itself the 

 result of change in the vapor of paraffine and other hydrocarbons of the oily 



characters. 



" It seems, therefore, a correct deduction from observation and experi- 

 ment, that gas carbon is not produced from olefiant gas by deposition, but 

 is a product of changes caused by heat in vapoi's of hydrocarbons, and 

 that this allotropic carbon, in other cases, forms in the presence of vapors, 

 which can transport carbon in the vesicular state." 



ON THE EXISTENCE OF SILVER IN SEA-WATER. 



MM. Malaguti, Durocher and Sarzeand, French chemists, some years 

 since detected and estimated the amount of silver in sea-water. They had 

 suspected its existence and obtained it by passing sulphuretted hydrogen 

 through large quantities of water, and also by fusing the salts obtained on 

 evaporation with litharge and subsequent cupcllation. 



According to the results obtained, a cubic mile of sea-water was esti- 

 mated to contain ten pounds and three-quarters of silver. Analyses by the 

 same chemists, of marine plants, gave confirmatory results. The silver, 

 however, being present in larger quantity. 



As a solution of chloride of silver in chloride of sodium is instantly 



