SENS EAT eRe oP 
La Ta eee 
eC ee EMS eg ae ET CARBET URINE t) SepPmR SY Yn gS ane 
JSean-Baptiste-André Dumas. 297 
the mean of those of the other two members. Later, he came 
to regard these triads as parts of more extended series, in each 
of which the atomic weights increased from the first to the last 
element of the series, by determinate, but not always by equal 
differences, the values being, if not exact multiples of the hy- 
drogen atom according to the hypothesis of Prout, at least mul- 
tiples of one half or one quarter of that weight. There can be 
no doubt that these speculations were more fanciful than 
of the same kind; but with him these speculations were 
merely the ornaments, not the substance of his work, and they 
e 
ed, were displayed throughout, and the enthusiasm of a 
French audience added to the animation of the scene. 
£ : 
trast to those of Faraday. Both were perfect of their kind, 
but very different. Faraday’s method was far more simple and 
He exhausted the subject which he treated, and was able to 
throw a glow of interest around details which by most teachers 
Would have been made dry and profitless. 
Two volumes of Dumas’s Lectures have been published ; 
