S. D. Hayes on the Distillation of Petroleum Naphthas. 185 
in two and a half and three and a half minutes respectively ; 
and the former evaporated completely in about two-thirds o 
the time required for the other.” 
This peculiarity of petroleum naphtha has been so often ob- 
Within the past year an apparatus has been erected in Boston, 
Zh: Wi i 
bottom of each cylinder, ending there and starting out from the 
top of each again to connect with the bottom of the next; it 1s 
The cylinders are provided with glass tube guages, so that the 
changes occurring inside may be watched, and the whole appa- 
matus and contents are maintained under a pressure of about 
fifty pounds to the inch when in operation. oe 
getl this apparatus the steam and naphtha vapors are he ~ 
sielleny the upper part of the cylinders, above the liquid, 
— ressure, and at a temperature of about 212 ae re 
much above the boiling point of the naphtha, but never so Aig: 
& 300° F.; and the decompositions occur in the vapors 
Sather than in the liquid, light uncondensable gases and va : - 
ng upward, and heavy oil falling down into the naphtha 
‘teataak The apparatus was operal continuously by pum : 
Mg in naphtha at intervals as it was consumed, and after 
