CHEMISTRY: RICHARDS AND DAVIS 
51 
the cover of the bomb. The foil was soft enou,gh to conform per- 
fectly to the double rim of the lower part of the bomb, without break- 
ing; the lead was soft enough to 
secure complete closure, and the 
gold wholly protected the lead. 
If the gold foil is pressed closely 
against the steel top of the bomb, 
there is little danger of its melt- 
ing and if an accident hap- 
pens, the foil is readily replaced. 
Accordingly, this method was 
uniformly used in the present 
research. 
The detrimental effect of fric- 
tion of the steel screw-cap 
against the movable steel cover 
was greatly diminished by the 
use of a thin, smooth, fiat ring 
of phosphor-bronze between 
these two parts. Thus rupture 
of the platinum lining was 
avoided, and the closure greatly 
facilitated. 
The insulation of the wire for 
conveying the current necessary 
for the ignition was improved by 
making the conical piece (passing 
through the cover) of steel, not 
platinum, and insulating this 
from the cover by a thin layer of 
mica. A stout thread and nut, 
Hkewise insulated, on the outside, 
permits forcing the strong steel 
cone so firmly into place that 
the arrangement is wholly gas-tight. Into the base of this cone a 
thread is tapped for the stout platinum wire used to conduct the 
current, and the iron is protected by a wide platinum nut, which is in- 
sulated from the cover by mica. Thus the platinum wire is very firmly 
held in place and yet may be easily unscrewed, and the insulation of 
the steel cone remains undisturbed indefinitely. Figure 1 records all 
these improvements. 
FIG. 1. NEW FEATURES IN CALORIMETRIC 
BOMB 
DE, steel conical plug; F, steel nut holding 
plug in place; G, mica insulation; H, platinum 
nut protecting mica and clamping /. /, plati- 
num rod for filing connection; H, gold lining to 
cover protecting lead washer N; L, phosphor- 
bronze ring to prevent friction of screw-cap Q 
on steel lid T. 
