550 Notices respecting New Books. 



it, but when moist the first is reddened and the latter be- 

 comes brown, owing to the liberation of boracic acid. 



I am now engaged in examining the effects of passing 

 some of the volatile metallic chlorides into absolute alcohol ; 

 and I am not without hope that I shall be able in this way 

 to form some metallic aethers. 



Since writing the above, I have seen in the last number of 

 the Annates de Chimie, which has just reached us, a notice 

 that M. Ebelmen has also succeeded in forming the tri- 

 basic aether I have now described, and has also formed a 

 similar compound with oxide of methyle. Our results appear 

 to be almost identical, excepting that his numbers approach 

 the calculated ones somewhat more closely than my own. 



LXXVI. Notices respecting New Books. 

 Guide to the Geology of Scotland. By James Nicol. Edinburgh. 



SCOTLAND, regarded geologically and in a general view, may be 

 considered as a trough, one side of which consists principally of 

 mountains of primary, the other of mountains of transition rocks. This 

 trough is filled with strata of old red sandstone and coal-measures, 

 through which trap rocks intrude. Its axis is a line passing near 

 Irvine, Bothwell and St. Andrews, from W.S.W. to E.N.E. To 

 this axis its limits both above and below are parallel ; the one boun- 

 dary, viz. that on the north-western side, passing from Greenock to 

 Stonehaven, the other, viz. that on the south-eastern, from Girvan 

 to Dunbar. This trough contains the basins and friths of the Clyde, 

 the Tay, and the Forth, though not the higher valleys of these rivers, 

 as the sources of the Clyde are in the transition mountains on the 

 south-east, and those of the Tay and the Forth are in the primary 

 mountains on the north-west. Its surface is a gently undulating 

 plain, beneath which are the evidences of many long extinct animal 

 and vegetable creations, and which is now occupied by a vast popu- 

 lation, whose subsistence depends ultimately upon its peculiar mi- 

 neral and geological properties. 



The primary mountains, which form the north-western side of 

 the trough, are the loftiest and the most rugged and barren in Great 

 Britain. Although they include vast beds of slate, together with 

 large and numerous patches of granite, and some rocks of very in- 

 ferior extent and importance, yet their most abundant constituent is 

 gneiss. The appearance of the country consisting of this rock, 

 which occupies more than a third part of the entire surface of Scot- 

 land, is described by Mr. Nicol in the following graphic terms : — 

 " Occupying large tracts of the central highlands, the characters 

 which gneiss impresses on the sceneiy are very distinctly seen. It 

 is the least picturesque and most monotonous of the primary rocks, 



