82 



SCIENCE-GOSSIP. 



Surely these facts must have come within the range 

 ■of common observation. 



Varying degrees of rhythmic growth may not 

 always result in lobed leaves in its aspects of 

 vigorous growth, or of entire leaves in its weaker 

 ones, because other factors interfere. We may not 

 know just what these incidental forces are, though 

 we may feel sure they exist. For instance, on the 

 common red cedar we may note two distinct forms 

 of foliage ; on the weaker, half-starved branches 

 the leaves are like needles and resemble those of 

 the common juniper, but on the more vigorous 

 branches there are seemingly no leaves at all. We 

 have to say "seemingly," for indeed there are 

 really leaves, as really so as on the weaker ones, 

 but the peculiar growth-energy of these more 

 vigorous branches causes them to become connate 

 with the stems. On a branch a year or two old we 

 can easily separate these connate leaves from the 

 true bark formed beneath. 



That there is no necessity for bringing in 

 hybridity to account for the occassional aberra- 

 tions from the normal form we meet with is well 

 known to those nurserymen whose business it is 

 to raise trees in great quantities. There are just 

 as many and just as striking variations among 

 genera consisting of a single species, or ot species 

 wholly isolated from other species of the genus, 

 as where there are several. The European 

 oak, ash, linden, beech, and many others, 

 furnish illustrations. The English oak, Quercus 

 robur especially, will furnish scores of variations 

 that have been selected from the seed-beds of 

 nurserymen, and given distinctive names. Many 

 of these differ from each other by characters quite 

 as striking as those which distinguish American 

 oaks from each other ; but we know they are not 

 hybrids because there was no other species with 

 which they could intercross, and they are not 

 regarded as species because of their derivation from 

 Quercus robur. This would not be a true test 

 of specific rank. It still savours of the old 

 doctrine of the special formation of species, 

 which we know is not true. With our modern 

 experiences we may expect occasional wander- 

 ings from a general character as a result of 

 an unusual expenditure of force. Usually 

 these displays of energy are not able to 

 maintain themselves. Seedlings fall back to the 

 habits of their ancestors. If, however, they 

 should be able to maintain themselves, they are 

 entitled to rank as species. They are species and 

 nothing else. 



Seeing, as we must, that all this is so, and must 

 be, why should we refer to hybridity to account 

 for individual changes, especially as the warmest 

 advocates of natural hybridity rarely get beyond 

 ' ' supposition ' ' in any case ? 



{To be continued.) 



NOTICES BY JOHN T. CARRINGTON. 



Electricity and Magnetism for Beginners. By F. W. 

 Sanderson, M.A. 245 pp. 8vo, with 116 illus- 

 trations. (London and New York : Macmillan 

 and Co., Limited, 1897.) Price 2s. 6d. 



The object of this book is to introduce boys to 

 the general subjects treated in its pages ; from 

 them they may get a working knowledge of the 

 application of electricity to man's requirements. 

 Every experiment has been practically worked out 

 by the author, and all appear to be within the 

 reach of a beginner. We can recommend the work 

 for schools and young people who are prepared to 

 help themselves to such necessary knowledge. 



British Game Birds and Wild Fowl. By Beverley 

 R. Morris, M.D. Revised by W. B. Tegetmier, 

 P'.Z.S. Parts iii. and iv. Super royal 8vo, with 

 coloured plates. (London : John C. Nimmo, 1897.) 

 Price 2s. 6d. per part, net. 



Part iv. completes one third of this handsome 

 work, which we have already noticed in May and 

 June last. The parts before us contain nine 

 plates between them. They finish the grouse, 

 partridges and quails, and end with the two species 

 of bustard, now so rarely observed in Britain as 

 casual visitors. We should like to have seen some 

 more notices of the occurrences here of these rarer 

 birds since the publication of the first edition of the 

 work, as it is well to have all information about 

 them as complete as possible. 



Mineralogical Geology : A Synopsis for the use of 

 Students, to accompany W . and A. K. Johnston's 

 Geological Map of the British Isles By Alexander 

 Johnstone, F.G.S. 198 pp. 8vo, and 14 plates. 

 (Edinburgh and London: W. and A. K. Johnston, 

 1897.) Price (with coloured map) 23s. 



This useful book is a supplement to the hand- 

 some map, which measures fifty inches by forty- 

 three inches. The map was originally compiled 

 by Sir Archibald Geikie, LL.D., the Director- 

 General of the Geological Survey of Great Britain ; 

 but it has been revised and extended by Mr. 

 Alexander Johnstone, F.G.S. It forms, with its 

 numerous sections, as complete a map for geological 

 purposes as one could desire, and should be 

 hung in every schoolroom in the kingdom. 

 With its aid and that of any good text -book 

 on geology an intelligent person could instruct 

 schoolboys and girls sufficiently to let them under- 

 stand the origin of their respective neighbour- 

 hoods. The accompanying book gives a sketch of 

 the science of mineralogy, with localities for 

 minerals in Britain. Many persons who know 

 little of the subject will find pleasant surprises in 

 store for them, when they discover how many rare 

 minerals and gems are within their reach in these 

 islands. Being alphabetically arranged, they will 

 soon know that we have, among many others, 

 amber, amethysts, beryl, cat's-eye, chrysoberyl, 

 garnet, jasper, moonstone, moss-agates, onyx, opals, 

 topaz, besides gold, silver, platinum, copper, etc., 

 among the precious metals. 



