346 
MR. JOHNSTON ON THE CONSTITUTION OF THE RESINS. 
6. It appears then that the resin obtained by digesting the crude labdanum of 
commerce in cold alcohol (083), is represented by C 40 H 33 0 8 , while that obtained by 
the same means from the crude resin previously boiled in water = C 40 H 33 0 7 . Is 
this difference owing to a species of transformation of the resin, or to the extraction 
by the water of a substance soluble both in water and alcohol ? 
To determine this point, I evaporated the bitter aqueous solutions obtained respect- 
ively by boiling the crude labdanum in water, and the substance extracted directly 
by alcohol from the crude resin. In both cases a small quantity of bitter extractive 
matter was left, which gradually attracted moisture from the air, but which was not 
subjected to any further examination. The presence of this substance had caused 
the difference between the results of the two series of analyses, and the close accord- 
ance of the first series with the formula C 40 H 33 O s is probably only accidental. 
The pure resin of labdanum, therefore, may be considered as represented in con- 
stitution by the irrational formula C 40 H 33 0 7 . 
XII. Berengela Resin. 
Under the name of Berengela resin or Berengelite*, I some time ago published a 
* The specimens of the substance for which I propose the name of Berengelite, were given to me by my 
friend Mr. Fryer, of Whitley House, near North Shields, and were obtained by him during his residence in 
South America. Of the circumstances under which it occurs, Mr. Fryer thus writes to me : — 
“ Of the resin or asphaltum from South America, I can unfortunately give you but a very imperfect account. 
I one day found in the yard of the Custom-house at Arica, a large convoy of llamas loaded with it, and all the 
information I could obtain from the men having charge of it was, that they brought it from St. Juan de Be- 
rengela, about 100 miles from Arica ; that it was found in very large quantities, and formed, according to their 
description, something like a lake resembling the pitch lake of Trinidad. It is extensively used for paying 
boats and vessels at Arica, and, I believe, on the whole coast of Peru.” 
This substance is hard, brittle, may be scratched by the nail, has a resinous fracture and lustre, is of a 
dark-brown colour, with a tinge of green, hut gives a yellow powder. The external appearance of the masses, 
as they were brought home, appears to indicate that the whole had formerly been in a softer state so as to yield 
easily to compression. It is insoluble in water, but dissolves readily and in large quantity in cold alcohol or 
ether, giving brown solutions. A small residue of earthy impurities is left. By evaporating the alcoholic 
solution, the resin is obtained of greater transparency, transmitting light of a bright-red colour, fusing easily 
on the water-bath, and remaining soft and unctuous at the ordinary temperature of the atmosphere. It gra- 
dually recovers its brittleness, but after the lapse of three or four months it is still soft, and adheres in some 
measure to the fingers. This property appears to be possessed by many other resinous substances, and ex- 
plains the semifused appearance of the imported masses. 
It has a peculiar, unpleasant, resinous odour. After fusion for some time at 212° Fahr., the unpleasant 
odour disappears, and is succeeded by an agreeable fragrance. On cooling again, it assumes, after some time, 
its original smell. When chewed in the mouth, it imparts a slight sensation of bitterness ; but the alcoholic 
solution has a disagreeable very bitter taste. 
Like most other resins, it is nearly insoluble in a concentrated solution of caustic potash. Boiled in a 
more dilute alkali it gives a yellow solution, from which the resin is again precipitated by acids. The alcoholic 
solution gives with a similar solution of acetate of lead, a copious yellow precipitate. It is, therefore, an acid 
resin. Its alcoholic solution is rendered milky by liquid ammonia, and passes milky through the filter. — 
London and Edinburgh Journal of Science, Third Series, vol. xiv. p. 89. 
