December 22, 1892 J 



NA TURE 



^11 



The progress of private electric lighting is simply 

 astonishing, the gas engine being generally the motor 

 used. Many of these engines are run by the Dowson 

 gas, made on the spot, thus rendering a supply of illu- 

 minating gas unnecessary. 



The author treats somewhat in detail the cost of electric 

 lighting in a house, but as this largely depends on the type 

 of pendants, brackets, &c., used, the outlay naturally 

 varies considerably. The most serious item in the main- 

 tenance of an installation is the breakage of the lamps. 

 The author rejoices that this monopoly of manufacture 

 will soon expire, when competition will place better lamps 

 on the market at half the present cost. 



Taken as a whole this little book is interesting and 

 useful. It will certainly help the uninitiated consumer 

 to study intelligently the principles of electric lightirrg, 

 and render his conception of necessary expenses when 

 installing the light more sensible. 



OUR BOOK SHELF. 



Grasses of the Pacific Slope ^ includinj^ Alaska and the' 

 adjacent Islands. Part I. By Dr. Geo. Vasey, Botanist, 

 U.S. Department of Agriculture. 8vo, 50 plates, with 

 descriptions. (Washington : Government Printing 

 Office, 1S92.) 

 The botanists of the United States Department of Agri- 

 culture are working very energetically, and the importance 

 of the herbarium, library, and its publications is increasmg 

 year by year. The present work is part of a series of 

 illustrations of the North American grasses, of which we 

 have already noticed two parts, together making one 

 volume, devoted to descriptions and figures of the char- 

 acteristic species of the South-Western States. The 

 present part, which will constitute half a volume, is 

 devoted to California and the Western States. Dr. Vasey 

 tells us in his introduction that the grasses which are 

 known to grow on the Pacific slope of the United States, 

 including Alaska, number not far from 200 species, which 

 is nearly twice as many as we get in the British Islands. 

 They are all specifically distinct from the grasses growing 

 east of the Mississippi, and also mostly distinct from the 

 grasses of the plains and of the desert, except in that part 

 of California which partakes of the desert flora. A con- 

 siderable number of the grasses of the mountainous 

 regions of California, Oregon, and Washington reappear 

 in the mountains of Idaho, Montana, and the interior 

 Rockies. The interior of California is a dry region, 

 verging in the extreme south into the desert country, and 

 is deficient in grasses, especially of those species which 

 form a continuous turf. In the present publication fifty 

 of the most interesting species are described and 

 illustrated. 



The descriptions are almost wholly the work of Dr. 

 Vasey's assistant, Prof. L. H. Dewey. The illustrations 

 are excellent, and are the work of various artists— F. 

 MuUer, W. R. Scholl, T. Holm, and others, and are 

 accompanied by full dissections. The species range under 

 the genera as follows : — Imperata, i ; Panicum, i ; Cen- 

 chrus, I ; Phalaris, 2 ; Hierochloe, I ; Aristida, i ; Spipa, 

 9; Oryzopsis, 2; Muhlenbergia, 5 ; Alopecurus, 7; 

 Agrostis, 6 ; Calamagrostis, 10 ; Deschampsia, i ; 

 Trisetum, 3 ; Orcuttia, 2. Only two out of the fifty species 

 are British, Alopecurus geniculatus and Deschampsia 

 £cespitosa. J. G. B. 



Aids to Experimental Science. By Andrew Gray. 



(Auckland: Upton and Co., 1892.) • 

 The chief interest of this little book lies in the fact that 

 it gives a glimpse of the science teaching in one of our 



NO. 1208, VOL. 47] 



colonies. It is a compilation of simple experiments in 

 mechanics, physics, chemistry, physiology and health, 

 and agriculture, to prepare students for what is known as 

 the Class D examination. Naturally, most of the experi- 

 ments are old ones, but here and there one may gather 

 a new idea. The portion dealing with physiology and 

 health has nothing to do with dissection, but consists of 

 expenments on ventilation, drainage, food stuffs, and the 

 like. An interesting piece of apparatus, devised by Prof. 

 Bickerton for showing the action of the lungs, is described 

 on p. 76. All the experiments are briefly but sufficiently 

 described, and many of them are illustrated. 



Science in Arcady. By Grant Allen. (London : 



Lawrence and Bullen, 1892.) 

 This volume willfully maintain Mr. Grant Allen's repu- 

 tation as a popular writer on science. The essays of 

 which it consists are written in a bright, lively style, and 

 may be read with pleasure even by original investigators, 

 for the truths with which they deal, if not new, are at 

 least presented from new points of view. Readers 

 who do not profess to know much about any particular 

 branch of science will find in these papers an excellent 

 introduction to some of the more attractive facts and 

 laws of the natural world. The volume includes some 

 archaeological essays, which show very effectually that an 

 antiquary has not necessarily much resemblance to Dr. 

 Dryasdust. 



LETTERS TO THE EDITOR. 



[ The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of. rejected 

 manuscripts intended for this or any other part 0/ Nature. 

 No notice is taken of anonymous communications.] 



Macculloch's Geological Map of Scotland. 



In a recent article in this journal Prof. A. H. Green writes as 

 follows : — 



" MaccuUoch seems to have projected, but-never completed, a 

 geological map of the whole of Scotland. The mateiials col- 

 lected by him were, however, utilized by the Highland Society 

 in the construction of a genera! map in 1832 " 



I am sure that nothing could he farther from the wish of the 

 Oxford Professor than to do an injustice to the memory of one of 

 the greatest of the pioneers in Hritish geology, and he will there- 

 fore forgive my calling attention to the following fjcts, which, 

 judging from a sulisequent letter in these pages, would seem not 

 to be generally known. 



During the last twenty years of his life Dr. John MaccuUoch 

 was engaged on a regular survey of Scotland, and in collecting 

 the materials for a geological map of the ciuntry. In the earlier 

 part of this period MaccuUoch seems to have availed himself of 

 the opportunities afforded to him as an official of the Board of 

 Ordnance to carry on his valuable geological explorations. But 

 during the latter part of the period he was regularly employed 

 by Government to complete his geological work, and was paid 

 by the Lords of the Treasury, who in the end published his 

 map. 



On July 28, 1834. MaccuUoch addressed to " His Majesty's 

 Treasury " a series of memoirs respecting the Geological Map 

 of Scotland, which was then completed. In these memoirs he 

 refers to the map as being then in existence, and gives the most 

 minute directions concerning the tints to be employed by the 

 colourists who were to copy the map, in order that it might cor- 

 respond with his original work. He also expressed his regret 

 that the imperfect topography of the map on which his re- 

 searches had to be recorded prevented the work from being as 

 accurate as he could have wished at certain points. 



Owing to < elays in issuing the Government publications — not 

 quite without parallel in more recent times— Macculloch's 

 " Memoirs on the Geological Map of Sc )tland" did not appear 

 till the year following his death (1836). The date at which the 

 firstjcopies of the map were issued it would probably be difficult to 

 determine, but as to the completion of the map before July 1834,, 



