ON THE PERCHLORATE OF THE OXIDE OF ETHULE. 33 
sequence of the distillation of the water, a reciprocal decom- 
position ensued, and a sweet ethereal liquid distilled into the 
receiver. This liquid is the perchlorate of the oxide of ethule. 
As this substance is extremely explosive, in order to pre- 
pare it with safety it is necessary to operate on small quanti- 
ties. We have employed from seventy to ninety grains of 
crystallized sulphovinate of barytes, with an equivalent pro- 
portion of perchlorate of barytes ;* but we would recommend, 
especially on first performance of the experiment, the employ- 
ment of considerably smaller quantities. The salts should be 
intimately mixed in a mortar, and placed in a small retort at- 
tached to a refrigerator containing ice, and a receiver similarly 
cooled. The retort is to be heated in an oil-bath, in which a 
thermometer is suspended, so as to indicate the temperature. 
A wooden screen, furnished with openings, covered with thick 
plate-glass at such intervals as to afford a full view of the dif- 
ferent parts of the apparatus, should be erected in front of it, 
and strings passed around the screen and attached to a bar tra- 
versing on a pivot, and supporting an argand spirit lamp, by 
which heat is communicated to the oil-bath, so as to enable the 
flame of the lamp to be removed from or applied to the appa- 
ratus, according to the indications of the thermometer, without 
exposing the person of the operator. After the heat has 
reached 212° F., below which the salts employed do not react 
on each other, it should be raised very gradually, and the dis- 
tillation finished below 340° F. Under these circumstances but 
little danger is to be apprehended from the retort, but the 
ether in the receiver must be treated with the greatest caution, 
since it has exploded in our hands in attempting to remove it 
with a pipette from the stratum of water which covers it. 
* The amount of barytes in the perchlorate should be ascertained by an 
experiment, as it retains water with great tenacity. It may be worth while 
to mention, that the perchlorate of potassa cannot be substituted for the 
perchlorate of barytes, since the sulphovinate is decomposed without act- 
ing on it. We were equally unsuccessful in an attempt to procure the 
ether by the distillation of perchlorate of barytes and concentrated sulpho- 
vinic acid. 
VOL. VII. NO. I. 5 
