16 
Mr. Charles F. Ravis then read a paper on " Amber," communi- 
cated by Mr. Philip John Butler, of London. The speaker recalled the 
fact that about two years ago he had exhibited to the society some beauti- 
ful specimens of amber, specially with reference to the insects therein 
contained, and had then made a short communication upon the subject. 
These specimens had been lent by Mr. Butler, who had since been pursu- 
ing his researches, which were embodied in a paper read at the Linnean 
Society in London, on December 21st, 1865. This paper Mr. Ravis read, 
adding also a few remarks of his own in the course of it. 
That amber was a fossil resin, and that most of what was obtained at the 
present day was disrupted from the submerged forests under the Baltic 
Sea, was now generally admitted. Its resinous character was known in 
the first century of the Christian era, although some of the ancients adopted 
the wildest theories respecting it, instances of which were given from 
Sophocles, Ovid, and other writers. That many of the ancients were wrong in 
their conclusions was certain, and it was equally certain that many in our own day 
were equally mistaken in supposing specimens to be amber which were only recent 
resin. Gum animi frequently contained insects, and was hence often confounded 
with amber, even in museum specimens, and instances had occurred of some 
authors, in entomological catalogues, actually mingling fossil species of insects in 
amber with existing species in modern resins. The weight of the largest piece of 
amber in the British Museum was 41oz., but at Berlin there were larger speci- 
mens. The chief use of amber was in connexion with meerschaum clay, animi 
being used for varnish. 
Mr. Rayis here read some notes on two recent resins, confounded with 
amber, viz., copal and animi. Copal was the Mexican term for gum as well 
as resin, the resin so called being the produce of Rhus Copallinum ; it 
rarely or never contained insects. Animi was a product of the Eastern hemi- 
sphere only ; it exuded from Vateria Indica, a gigantic tree of Malabar, and was 
formerly sold in Indian bazaars under the term Sundross. The Portuguese knew 
it in 1498, and on settling in South America in 1549 they misapplied the term 
animi to the resin of New Spain. In continuing Mr. Butler's paper, the following 
ready mode of distinguishing amber from animi was given. The specimen being 
polished, was to be placed in cold water, which should be gradually heated to 
boiling ; animi thus treated, frequently even before the water reached 200°, but 
always on boiling, lost its brilliancy, and was much altered in appearance and 
shape, while amber was unchanged. Some instances were given of specimens of 
amber containing fish, which were evidently manufactured, and not of natural 
occurrence. 
The author then described his microscopic investigations into the cloudiness 
in amber, an appearance which was due to the presence of an immense 
number of small cavities, of very various shapes, some containing fluid only, 
others probably gas, or even vacuity, and others again were filled with fluid 
which had a bubble of gas in it. Mr. H. C. Sorby, F.R.S., well known for his 
researches on the microscopic structure of crystals, had examined these, and shown 
that several gave a black cross with polarised light, indicating a want of pressure, 
as though the material surrounding the bubble had become somewhat solid and 
