Jtdy 22, 1875] 



NATURE 



231 



former deriving their nourishment entirely from living- 

 organic matter, in some cases animal, in others vege- 

 table ; the latter from organic matter in a state 

 of decay ; but neither having the power of " assimi- 

 lating," or obtaining their food-materials direct from 

 the atmosphere and the inorganic constituents of the 

 soil. Saprohgnia and Cordiccps are as fully entitled 

 to the designation of carnivorous or even insecti- 

 vorous plants as Dioncpa or Droscra. The difference lies 

 chiefly in the localisation of the power of absorption, 

 which we have not generally considered to reside in the 

 foliar organs. By far the most interesting facts brought 

 out in this volume — and we think they are amongst the 

 most important published for many years — are the changes 

 from neutral to acid in the nature of the secretion poured 

 out by the glands of Drosera on their excitement by 

 contact with soluble nitrogenous substances ; and the 

 alleged " reflex " excitement of the tentacles of Drosera. 

 It is impossible to foretell to what these discoveries will 

 lead. We cannot but think that this volume will serve, 

 as the previous ones from the same hand have done, to 

 act as finger-posts to direct future observers in those lines 

 of research which are likely to be the most fruitful and 

 profitable. ALFRED W. Bennett 



OUR BOOK SHELF 



Proe^ress-Report upon Geographical aiid Geological Ex- 

 ploratio7is attd Surveys west of the \ooth Meridian in 

 1872, under the direction of Brigadier-General A. A. 

 Humphreys, Chief of Engineers, U.S. Army. By First 

 Lieutenant G. M. Wheeler. — Also Topogrciphica.1 Atlas 

 to illustrate Geographical Explorations west of the 

 looth Meridian. (Washington : Government Printing 

 Office, 1874.) 



Our readers are no doubt aware that a large area of 

 the Western States of America is overrun by a number of 

 expeditions intended mainly for the topographical and 

 geological survey of that immense region. Some idea of 

 the number and constitution of these parties will be 

 obtained from two articles in Nature, vol. viii. pp. 331 

 and 385. The " Progress-Report " for 1872 of that under 

 charge of Lieut. G. M. Wheeler contains only brief notes 

 of the work done by the various parties ; detailed reports 

 will, no doubt, be published eventually, and will occupy 

 several volumes, besides atlases. The present brief report 

 comprises notes of work done, not only in geology and 

 topography, but also in astronomy, meteorology, natural 

 history, ethnology, and photography. Some idea of the 

 amount of work done may be obtained from the fact that 

 the areas covered topographically during the summer 

 months of 1872 exceeded 50,000 square miles lying in 

 Utah, Nevada, and Arizona. The length of hncs in the 

 vicinity of which surveys were made is 6,127 miles, in 

 addition to which other 2,067 miles had to be travelled 

 for various purposes. A large portion of the present pub- 

 lication is occupied with reports on the numerous mining- 

 stations which have been established in the district 

 surveyed, as also on irrigation, agriculture, routes of com- 

 munication, timber lands, and Indians ; from the latter 

 the expedition met with no interference, though of course 

 it was accompanied by a miUtary escort. One of the 

 principal features of this report are the lithographic illus- 

 trations from camera-negatives of some of the magnificent 

 caiions on the Colorado River ; one of these illustrations 

 gives a fine idea of a rain-sculptured rock at Salt-Creek 

 Cafion, Utah. 



The atlas which accompanies this Report is a mag- 

 nificent work and reflects great credit on the U.S. 



Government and especially on the topographic sec- 

 tion of Lieut. Wheeler's Expedition. Besides a general 

 map, it consists of eight sectional maps in photo- 

 lithography on the scale of one inch to eight miles, suffi- 

 ciently large to give one an excellent idea of the nature of 

 the country which has been surveyed. The maps are the 

 results of the expeditions under Lieut. Wheeler in the 

 years from 1869 to 1873, and embrace parts of California, 

 Nevada, Utah, and Arizona. Ever>' important feature is 

 shown by characteristic and intelligible signs — mountain 

 ranges, plateaux, canons, bluffs, hills, craters, salt beds, 

 sands, marshes, rivers, creeks, springs, &c., not to men- 

 tion artificial features, as roads, trails, railroads, towns, 

 &c. We understand that maps of the whole region west 

 of the looth meridian are to be published on this scale, 

 and in some cases on a more extended one. It will be a 

 magnificent work when complete, a work of which any 

 country might be proud. 



Nach den Victoriafdllcti des Zambesi. Von Edouard 



Mohr. 2 vols. (Leipzig : Hirt und Sohn, 1875.) 

 Notwithstanding that Herr Mohr went over ground 

 that had been traversed previously, a considerable part of 

 it being included in Livingstone's earlier travels, yet his 

 book contains a great deal that is new and well worth 

 publishing. From the time that he left Bremen in 

 November 1868 till his departure from Africa in the 

 beginning of 1871, the interest of his narrative never 

 flags ; the book contains frequent passages of genuine 

 eloquence, quite free from bombast or affectation. During 

 part of his journey, Mohr had as his companion the 

 geologist Adolf Pliibner, and their starting-point for the 

 Victoria Falls was Durban. From this point they went 

 almost directly to the falls, Hiibner, however, leaving his 

 companion before the Zambesi was reached, in order to 

 visit the recently discovered South African diamond 

 fields. Mohr, as we have indicated, tells the story of his 

 journey and its many interesting incidents, particularly 

 well, although, as might be expected, there were none of 

 the dangers to be encountered which face explorers in 

 less frequented parts of Africa. The book is full of valu- 

 able information of all kinds concerning the places 

 touched at or visited both on the voyage out and on the 

 journey from Durban to the Zambesi. The book must 

 be considered as a specially valuable contribution to our 

 knowledge of the natural history and geology, as well as 

 to the geography of the district passed through. To the 

 geographer the narrative will be found of very great value, 

 as it contains a record of the carefully ascertained latitude 

 and longitude of the prihcipal points at which halts were 

 made. Appended is a valuable paper by Hiibner on the 

 South African Diamond Fields. The work is illustrated 

 by many good woodcuts and a few brilliant chromo- 

 lithographs. There is also a small but clear map of 

 South Africa, showing not only Mohr's route, but the 

 routes of the principal travellers from Livingstone (1841) 

 downwards. Altogether, the work must be considered 

 a really valuable contribution to our knowledge of the 

 region traversed, and seems to us well worth translating 

 into EngUsh. 



LETTERS TO THE EDITOR 



[ The Editor does not hold himself responsible por opinions expressed 

 by his correspondents. Neither can he undertake to return, 

 or to correspond with the writers of, rejected manuscripts. 

 No notice is taken of anonymous communications.'^ 



Spectroscopic provision of Rain with a High Barometer 

 That the spectroscope should play a part in the prediction of 

 weather for the common purpose's of life was an early thought 

 with many ; but I have not heard of its resources beiug very 

 distinctly appealed to in the late series of most memorable 

 fieTfoipa of the atmosphere which have passed over this country, 

 setting nearly at naught most other methods of prediction. 



