MR. JOHNSTON ON THE CONSTITUTION OF THE RESINS. 
367 
water it loses its transparency and becomes white and opake, but imparts no colour- 
and long- dried at 212° Fahr., it left when 
ing matter to the water. Thus prepared 
burned in the air 0T0 per cent, of ash. 
A. 8‘31 grs. (8-302 grs. pure resin) 
B. 8"04 grs. (8'032 grs. pure resin) 
C. 7'46 5 grs. (7*458 grs. pure resin) 
A. 
B. 
Carbon 
78-93 
78-15 
Hydrogen 10-57 
10-30 
Oxygen 
10-50 
11-55 
100 
100 
gave 
C = 23-7, 
and 
IT = 7-9 
grs 
gave 
C = 22-71, 
and 
II = 7-45 
grs, 
gave 
C = 21-26, 
and 
H = 6-998 
grs. 
C. 
C 40 H 32 0 4 gives 
78-82 
79-275 
10-43 
10355 
1075 
10-370 
100 100 
II. Resin B. of Elemi ( very sparingly soluble in cold , more largely in boiling Alcohol, 
out of which it crystallizes on cooling). 
This resin remains in the form of a white powder when the natural elemi resin is 
exhausted with cold alcohol, as long as a coloured solution is obtained. This white 
powder dissolves in boiling alcohol, and yields the pure resin in the state of minute 
white crystals as the solution cools. The constitution of this resin appears to be 
pretty well established, having been analysed by Hesse, Rose, and Marchand, with 
results which are very closely accordant. 
The specimen I analysed, after drying between folds of bibulous paper, had been 
long heated at 200° Fahr., and was then in the state of a white powder. 
A. 6’893 grs. gave C = 2T265 grs., and IT = 7*395 grs. 
B. 6‘76 grs. gave C = 20*78 grs., and IT = 7*2 grs. 
These results compared with those of the other experimenters, give per cent. 
Hesse. 
Carbon 85*36 85-06 
Hydrogen 1T51 11*54 
Oxygen 3T3 3*40 
Rose. 
85-11 85-61 
11-79 11-83 
3-10 2-56 
Marchand. 
85-54 85-59 
11-61 11-59 
2-85 2-82 
Johnston. 
85-30 85-00 
11-92 11-83 
2-88 3-17 
100 100 
100 100 100 100 
100 100 
The only difference of any consequence among these analyses is in the amount of 
hydrogen. I have given only two of the results published by each of the above che- 
mists, but in three others published by Rose, the hydrogen amounted to 11*85, 11-89, 
11-98 respectively. Finding the quantity of hydrogen deduced from my first analysis 
to be so high, I used greater precautions in pumping out the hygrometric moisture 
in the second, but without bringing it much nearer the results of Hesse or Marchand. 
Still the formula adopted by Hesse is that which must be adopted as the most pro- 
bable, if any allowance is to be made in the analyses of Marchand, Rose, and my- 
