Mr. F. Guthrie on the Preparation of the Double Aithers. 187 
funnel-tube. Double decomposition at once began ; heat was 
eyolved, the contents of the retort becoming liquid and boiling. 
The action was allowed to go on by itself for two or three hours, 
but was then assisted by the heat of a water-bath. After some 
hours’ digestion the contents of the retort ceased to boil. The 
clear liquid was then decanted from the iodide of potassium and 
excess of caustic potash and rectified. 
The rapidity with which the boiling-pomt rises from 100° to 
110° C., its constancy at and about that point, and the small- 
ness of the residue having a higher boiling-point, were evidences 
of the completeness of the reaction. In fact, after six rectifica- 
tions the weight of the double ether obtained was two-thirds of 
that of the amylic alcohol employed. It boiled at 111°, il yaa 
118° C., and gave on analysis (mean of two), 
CH" 0, C+H'O. Found. 
Ge Fy schic’s ene eek 71:66 
Bot barre ¢ AAC OD 14°27 
In the above process the excess of caustic potash combines 
with the water arising from the separation of the amylic «ther 
from the amylic alcohol, so that no water appears in the free 
state,— 
CH" 0,HO+2KO, HO+C* H®I=KI + KO, 2HO 
a Ou Le. 
There can be little doubt that analogous recompositions occur 
between the iodides of the other radicals and the solutions of 
potash in the several alcohols ; the chief point to be attended to 
being, of course, such selection of the two that the boiling-point 
of the product shall differ as widely as possible from those of the 
iodide and alcohol employed. The advantage of this mode of 
preparation consists wholly in dispensing with metallic potassium 
or sodium, metals which of course entirely lose value as soon 
as oxidized. 
It is clear that all such bodies may be regarded in three ways: 
as double ethers, as single ethers, or as alcohols, according to 
the general formulz 
C2m H2mt1 O, C22 H2+1 O, 
Cmtn Hmtn+l O 
Cmt+n P[_mtntl ti equivalent to Cmtn Yim+n+1Q, 
or 
((2m+n) Fy2(m+n)+1 O, HO. 
The action of pentiodide of phosphorus upon a member of this 
class seemed to promise to throw light upon the above question. 
Accordingly an ounce of the sethylate of amyle, prepared as above, 
