Bibliography. 171 
gramme of gaseous hydrogen gives heat sufficient to raise 62,535 
grammes of water 1° Fah. 
The average excess of hydrogen for the six varieties of coal tried by 
evaporation, as deduced from columns 18 and 14 of the table, is 4:636 
per cent. which, calculated after the manner of the European chemists, 
ought to possess an evaporative power of 2:814. This would raise the 
average of the 15th column from 10-700 to 13:514, as the calculated 
evaporative power of the unit of combustible matter, showing the calcu- 
lated to be 26-3 per cent. higher than the experimental effect. 
The data furnished by the preceding table afford the means of ascer- 
taining the proportion of its carbon volatilized in the distillation of the 
combustible matter in each kind of coal. 
The calculations prove that of its whole carbon constituent, the per 
centage volatilized was as follows— 
Cambria County coal, ; : : : 16°767 
Midlothian, new shaft, j : , 3 29-195 
Newcastle, t : 4 t : : 15-967 
Clover Hill, ; 3 : ; ‘ : 16:847 
Scotch Cannel, . ; ; & : ’ 24:169 
Caseyville, Ky., Cannel, . : : : 22°452 
And that the average was . ie : 20°883 
The identity of results obtained in the averages of the 15th and 18th 
columns should seem to demonstrate that the heating power of bitu- 
minous coal is proportionate to the carbon which they severally contain. 
3. Musée Botanique de M. Benstamin DeEtessert ; Notices sur les 
collections de Plantes et la Bibliothéque qui le composent ; contenant en 
outre des documents sur les principaux herbiers d’ Europe: par A. La- 
SEGUE. Paris: Fortin, Masson & Cie, 1845. 1 vol. 8vo, pp. 588.—Ba- 
ron Delessert, the proprietor of one of the richest herbaria and most 
complete botanical libraries of the world, is worthily distinguished, not 
ouly for the enlightened zeal which has prompted the collection of 
these treasures, and the knowledge which appreciates them, but also 
for the liberal manner in which they are thrown open to the use of men 
of science generally. As our author (the curator of this museum since 
the death of Guillemin) remarks, ‘these collections, brought together 
for the use of all, are constantly open to all, and the galleries of M. De- 
lessert serve as a centre of reunion for all the savans who choose to 
labor there ; thus renewing in our days the example given, at the com- 
‘mencement of this century, by the »celebrated Sir Joseph Banks.” 
This interesting volume is occupied with an account of the orgin of 
