Sir J. E. Smith's English Flora. 159 



ray then proceeds in the direction PQSO, to the eye at 0. The angle at C 

 should be a little less than a right angle, in order that when the eye ad- 

 vances to B, it may not see objects directly reflected from AB. A plate of 

 copper CN, pierced with a longitudinal aperture, as in Fig. 21, is then 

 placed from C to N. In this construction, and indeed in all, the prism 

 ABC, is greatly superior to a metallic mirror. M. Amici points out the 

 great utility of the camera lucida in lithography, as the drawing from na- 

 ture may be made at once upon the stone. 



Art. XXXII.— ANALYSIS OF SCIENTIFIC BOOKS AND 



MEMOIRS. 



1. The English Flora. By Sir James Edward Smith, President of the 

 Linnean Society. 2 vols. 8vo. Vol. I. 370 pp. Vol. II. 470 pp. 



It is now time that we should execute the agreeable task which we, 

 some time ago, promised to ourselves, of noticing more at large the two 

 first volumes of Smith's English Flora, the appearance of which was an- 

 nounced in the first number of our Journal. 



There are, perhaps, few countries of so limited extent that comprise 

 such a variety of plants as the British Islands ; particularly if we take in- 

 to account its marine productions ; although we must, at the same time, 

 confess that there are, comparatively, few vegetables that are peculiar to 

 these countries, few that are not found either in France, Germany, Den- 

 mark, Sweden, Norway, and Lapland. The variety of British produc- 

 tions to which we allude may, we think, be attributed to the extent of 

 the island from north to south, across 60° of latitude. Hence the plants 

 of the southern districts will be found to have many species in common 

 with France and Germany ; those of Scotland again, with the productions 

 of Sweden and Denmark ; whilst the great elevation of the hills in some 

 parts of the country induces a vegetation that may most aptly be compar- 

 ed with that of Norway and Lapland. Parallels of longitude seem to af- 

 fect, or to produce a difference in vegetation, much less than those of lati- 

 tude. Hence, the degree of elevation above the level of the sea being the 

 same, the plants of England and Scotland will equally be seen on the 

 continent of Europe in the same parallel oflongitude : and Ireland again, 

 will be found to have a vegetation scarcely different from those parts of 

 England and Scotland opposite to which it lies- The exceptions to this 

 rule are very few in number. The beautiful Menziesia po/ifolia, or St 

 Patrick's Heath, and the Saxifraga Geitm, with its numerous varieties, 

 are, we believe, only found truly wild in Ireland ; and the same may be 

 said of the Euphor-hia Hibernica ; but the two former are principally con- 

 fined to the western extremity of that island. We cannot satisfy ourselves 

 that the Aibulus is an aboriginal native of Killurney, where it grows with 

 Midi luxuriance ; but are rather inclined to annex some credit to the tra- 

 dition of its having been introduced by the monks of Mucross Abbey, 



