98 Scientific Intelligence. 
SCIENTIFIC INTELLIGENCE. 
I. CHEMISTRY AND PHYSICS. 
1. Electrolytic investigations.—Under this title Magnus has published 
an elaborate and important memoir reviewing the aia i B phen: 1 
vestigations std containing many new and import We shall 
here give — the author’s summary, referring “ay ibe cia to the 
original memo 
{1.) To axpiain the so-called double decomposition observed by Daniell 
and Miller, it is not necessary to assume an oxysulphion, oxynitrion, &e. 
This assumption is refuted by the fact that compounds like S+-40, N-+60 
are never separated at the positive electrode. It is true that at this elec 
trode a full equivalent of oxygen, corresponding to the metal separated, is 
found, but of the acid there is only a portion, frequently only 60 percent. 
By employing a porous diaphragm the remainder of the acid is found in 
the en ce 
2.) When several salts are present in the same solution, the current 
at a certain intensity decomposes only one of them. In like mannet 
the current only the salt, and not the water, is decomposed. There 
is therefore for every com und electrolyte a limit of intensity, at which 
only one of its constitu =e is decomposed. 
1en currents are employed the intensity of which is less than the 
can pass to this substance, or to the maximum of the substance which — 
can be decomposed in a given time with unchanged electrolytes and ul 
changed electrodes. 
(4.) This limit depends upon the size of the electrodes; on the decom 
posability of the different constituents of the electrolyte; and on the 
tive quantity in which they exist in it. 
(5.) Since, in the application of the merit intensity, the migra? may 
be nearer to or farther from each other, the a of the con- 
ducting substance which is decom a b same current me “he 
same electrodes is = same, whether the Rhee are nearer to or fat 
ther from each othe 
(6.) The limit of ‘the intensity is proportional to the magnitude of the. 
electrodes, provided that this section of the electrolyte is the same 
size of the electrodes, This $e orler es holds good wing only 80 
ras as the constitution of the electrolytes remains unchar 
7.) The conduetion of electricity through an electroly Z aa the de- 
composition which takes place thereby, may Regeey to the case of the 
induction = electricity upon insulated condue 
(8.) In this manner the Aosictor of the wo-talled double decomposition — 
raised by Daniell may be 
9.) It requires the same take ve separate a simple substance from & 
binary combination w is n necessary to separate it from a more comp™ 
saline compound. 
Es 
