Proceedings of the British Association. 367 
Mr. Mackay read the Report which he had been last year req 
ed to prepare, “On the Geographical Distribution of the Planes: of 
Ireland.” This contained a catalogue of one hundred and ninety five 
of the more remarkable species, with a comparative view of such as 
were common to the neighborhoods of Dublin, Edinburgh, and the 
south coast of Scotland. And Mr. Mackay then entered into some 
details illustrative of the more remarkable points of difference in the 
vegetation of Ireland and Scotland. This difference might be partly 
ascribed to the more southerly situation of Ireland, and the height 
of its mountains being inferior to those of Scotland. Its greater ex- 
posure to the influence of the western ocean gives it a moister cli- 
mate. Scotland is, in consequence, much the richer in alpine plants, 
and Mr. Mackay enumerated fifty five species of the more remark- 
able alpine and other plants natives of that country, which do not 
occur in Ireland. Many plants on the western coast are natives of 
the mountains of Spain and Portugal. A list was then given, in 
which twenty one species were enumerated as natives of Ireland, 
but which had not been found in any other parts of Great Britain, 
and it was very remarkable that several of these were also to be 
met with on the western side of the Pyrenees. In conclusion, Mr. 
Mackay proposed to continue his observations, hoping to present the 
Association with a more perfect list on a future occasion. 
Mr. Royle read a communication on Caoutchouc. 
Mr. P. Duncan detailed some observations on Marine Luminosity. 
Dr. Hancock read a paper “On the Cow fish, Manatus fluviatilis, 
of the inland waters of Guiana.” 
Dr. Macartney made some observations on the preservation of 
animal and vegetable substances from the attacks of insects. He 
employed a concentrated solution of equal parts of alum, nitre, and 
salt, mixed with an equal quantity of proof spirits and a little oil of 
lavender or rosemary. A forcible injection of this liquid into the 
arterial system would perfectly preserve a dead body for three or 
four months fit for dissection, and portions of one which had been 
thus injected, if rubbed over with pyroligneous acid, might be pre- 
served for any length of time. He recommended a coat of plaster 
of Paris to be daubed over succulent plants as a mode of preserving 
them, and, when dry, this might be easily removed. He noticed 
the entire preservation of some bodies found in the bogs of Ireland. 
Mr. Hope exhibited a collection of North American insects, prin- 
cipally Coleoptera, collected from the raw turpentine sent over to 
