1818.] Royal Society of Edinburgh. 299 



March 12. — A paper by Dr. Totness Fischer, "On the Anatomy 

 of Spiders," was read ; also a paper, by B. Bevan, Esq. " On 

 some Fossils in Leicestershire and Northamptonshire." 



ItOYAL SOCIETY OF EDINBURGH. 



March 2. — Dr. Murray read the first part of a paper " On the 

 Relation in the Law of Definite Proportions in Chemical Combi- 

 nations, to the Constitution of the Acids, Alkalies, and Earths, 

 and their Compounds." Its object was, to determine if the 

 composition of these substances, according to the theory which 

 he has lately proposed, be conformable to the law of definite 

 proportions. The part of the paper read extended to the acids 

 of which sulphur and carbon are the radicals, the vegetable acids 

 being comprised under the latter. A very strict coincidence is 

 found in the actual proportions, according to the theory, with the 

 law, so as to afford proofs even of the truth of the former ; and 

 some of the results display views very different from those which 

 have been hitherto proposed. The remainder of the paper will 

 be read on a succeeding evening. 



At the same meeting an abstract of a new paper, by Mr. Lau- 

 der Dick, on the Parallel Roads of Lochaber, was read. 



After considering the paper which he had prepared on the 



Earallel roads of Lochaber, since his second visit to that district, 

 e was satisfied that it would not be very intelligible if read to 

 the society, owing to the frequent reference to the map and 

 drawings. He therefore contented himself with a very few 

 remarks explanatory of the views he entertained of this interest- 

 ing subject. 



In a former paper he described the general nature of these 

 shelves : he has since ascertained, by several observations, that 

 they are perfectly horizontal. One very remarkable circumstance 

 attending them is, that in one or two instances, they can be 

 traced in a perfect circle, around little isolated hills, on a level 

 with the corresponding line on the sides of the valley. 



In his former visit to Glen Roy, he traced the shelves in that 

 valley only ; on the late occasion, however, he discovered that 

 they are also to be found in Glen Spean and Glen Gluoy. This 

 last valley contains one range, at an elevation 12 feet higher than 

 that of any of those in the other glens. The two shelves next 

 in altitude are to be found in Glen Roy alone. The uppermost 

 runs through both lower and upper Glen Roy, and loses itself in 

 the flat mossy ground, forming the summit level of the country 

 near the Loch of Spey. Besides these two shelves, which are 

 the particular property of Glen Roy, there is another at a lower 

 level, common to Glen Roy and Glen Spean. Its two extremi- 

 ties are to be traced, one on the mountain of Ben-y-vaan, near 

 Highbridge, and the other on the Bide of Aouachmore, one of 

 the Ben Nevis group, nearly opposite. This shell' may be fol- 

 lowed almost every where, in its progress through both glens. It 



