268 Scientific Intelligence. 
determined in a similar manner. [The author’s result in this case 
with those of Schneider and Marchand.] In the case of manganese the 
number 26 was found by igniting an artificial binoxyd in a current of 
hydrogen so as to reduce it to protoxyd. umas’ equivalent for man- 
anese differs so greatly from that of Berzelius, 27°6, as to make further 
researches desirable——w.¢.| The number 11 for boron is calculated 
d 
asily shown by agitating the chlorid with water 
when carbonic acid gas is disengaged. 
The author is still engaged with the subject of a revision of the equv- 
alents and the publication of his results—which cannot be looked for till 
the close of the present year (1858)—will be awaited by chemists with 
special interest. 
In order to exhibit the numerical relations between the equivalents of 
the different elements the author, after referring to the previous investiga- 
tions of Prof. Cooke, takes up in the first place the examination of cer- 
tain groups and series presented by organic chemistry. If we consider 
the homologous series C2Hs, CaHs, CeH7, &c., we remark at once that 
there is a common point of departure for and a common difference be- 
tween the equivalents of the successive terms. The formula a-+-nd rep- 
resents the generation of all these radicals, a being the equivalent of the 
first, and d the difference between the first and second term. The author 
remarks that if we did not know the law of progression we might easily 
be led to think that the ratio between the numbers 141 and 281, 127 
and 253, 113 and 225, is the simple ratio of 1:2, especially as chemis- 
of the elements rof, Cooke supposed the organic radicals a 
not always produced by addition but sometimes by substitution as we se? 
in und ammoniums. We may have for instance the following 
ammoniums 
a a+td a+2d a+3d a+-4d 
a atdtd’ at2d4d’ a+3d+a' 
a-+-2d’ atd42d' a+2d+2d 
a+3d’ a+d+3d 
atd+d’+d"+d’", 
where a represents ammonia NH4, and d, d’, &c. represent the equivalent 
of hydrocarbons of the series CnHn. : here 
In the next place there are certain radicals in organic chemistry W gk 
the fundamental molecule itself changes as well as the bodies added t0 
or substituted in it. Thus tin and ethyl form six molecular groupe 
sessing all the properties of organic radicals, If we represent et y 
and ethy) by d’ we have for the six species of stannethyl the formulas 
: a ; d’ 2a , 4a-+d 
it 4a+3d' 
4 ‘ 
