356 J. W. Mallet on the Atomic Weight of Lithium. 
cautiously added to the fluid in the flask from a pipette furnished 
with a small glass stop-cock and graduated to the one-fifth of a 
silver. ; 
Hence altogether 10°1278+0424=10:1702 grm. of silver had 
n used. 
10°1702 : 8°9942 :: 1849°66 feat of Ag): x 
ek : 
580-06—448-28 (equiv. of Cl)=86-78=equiv. of Li. 
This number agrees sufficiently nearly with those derived 
from the two former experiments to show that all three are de- 
serving of confidence. If we take the mean of the three, we 
shall have the number 86°89 for the equivalent of lithium ; and 
this may, I believe, be fairly trusted as a closer approximation 
to the truth than any of the numbers hitherto received, if we 
take into account the greater scale upon which the analyses have 
been made, and the difference in the methods pursued. For it 
will be observed that the effect of the difficulty in determining 
sulphate of baryta already mentioned (namely the adherence 0 
a little of the salt used for precipitation so as to scarcely permit 1ts 
removal by washing) will necessarily be to increase the appa 
a of sulphuric acid in the sulphate of lithia an- 
alyzed, and hence to give a lower equivalent for the alkali than 
the true one. But this is the method by which the results hith- 
erto most relied upon have been obtained. 
The number 86°89 on the oxygen scale corresponds to 6:95 
upon the hydrogen—thus making the equivalent of lithium 
almost exactly an even multiple of that of Sepdropett, in accord- 
ance with the analogy which seems to extend further and further 
through the list of elements, as our knowledge of their atomie 
weights becomes more exact. 
And further, if we take the mean of thé equivalents of potas 
sium and lithium, using 86°89 for the latter, we get— 
488°86 (Marignac) 
86°89 
.  2)B75°75. 
a.  987°87— almost exactly the equivalent 
of sodium (287°44) as determined by Pelouze. 
