52 



NA TURE 



\_Nov. 1 8, 1886 



without hardness, and hfe-like. The text is interesting, 

 and the number of food-grains described in excess of 

 what most of us were aware existed. Prof. Church com- 

 mences his work by what must have been to him a fami- 

 liar task — describing the chief constituents of food, 

 splitting up the sugars into their groups, and pointing out 

 the differences between true nutrients and food-adjuncts. 

 Part 2 is devoted to dietaries and rations. With Part 3 

 commences the peculiar merit and raison d'etre of the work. 

 After some remarks upon cereals generally, the reader is 

 introduced seriatim to no fewer than twenty-three 

 cereals, the only m:mber of the group conspicuous by its 

 absence being rye — a grain which occupies a very im- 

 portant place in Europe. The presumption is that it 

 does not occur in India, but such a presumption surely 

 presumes too much. Wheat is described as an annual 

 grass of unknown origin, but we scarcely see why this 

 nescience as to the origin of wheat should be especially 

 set forth. Are we to infer that barley, oats, maize, rice, 

 the millets, &c., are annual grasses of known origin ? If 

 so, would that the Professor had devoted a few lines in 

 each case to this particular point ! The origin of our food- 

 grains is a deeply interesting subject, veiled, we are afraid, 

 for the most part in mist, and only conjecturally outlined. 



The author disclaims any special originality, and 

 duly credits the works of Dr. Forbes Watson, and Messrs. 

 Duthie and Fuller, as well as other authors, as sources 

 from which he has industriously gathered information. 

 Messrs. Duthie and Fuller's work, however, dealt but 

 little with the chemistry or physiology of the plants they 

 described, and they treated more exclusively of the culti- 

 vation of the various crops. 



The interest of Prof. Church's book lies in the 

 illustrations, which are super-excellent ; in the analyses, 

 many of which were made in the author's own labora- 

 tory ; in fixing the nutrient-ratio and nutrient-value of 

 so many foods ; and, lastly, in the comprehensive view 

 given of Indian cereal and other crops. The Indian local 

 names and Sanskrit equivalents are also interesting. 

 These are taken by our author on trust, but all or many 

 of them also occur in Mr. Duthie's book, which would 

 be a guarantee of their correctness. 



John Wrightson 



Tobacco a Farmei-'s Crop. By Philip Meadows Taylor. 



(London : Edward Stanford, 1 886.) 

 This is a small book of seventy pages. The first 

 half is occupied by pleasant matter relating to the 

 history of tobacco in Europe not strictly or seriously 

 relevant to the title. The latter half redeems the 

 whole from the stigma of being unpractical. An in- 

 teresting account is given of the despotic regulations of 

 the " Regie des Tabacs," a Government Department 

 which grants licenses for growing, manufacturing, and 

 selling tobacco throughout France, and whose powers 

 extend to the nomination of the cultivators, the variety of 

 tobacco to be grown, the number of plants per hectare, 

 and even the number of leaves permitted per plant, so 

 that the unfortunate cultivator may and must give a per- 

 fectly accurate account of his yield down to a single leaf. 

 The methods of cultivation followed in France are 

 described plainly and apparently practically. The im- 

 portant question as to whether tobacco can be grown 

 profitably in England is answered unhesitatingly in the 

 affirmative, and a sensible scheme is propounded for 

 bringing its culture into harmony with the Excise. The 

 coldness exhibited by our Royal Agricultural Society 

 towards the tobacco movement last April is strongly anim- 

 adverted upon. As to our climate, Mr. Taylor writes 

 as follows : — " It is stated to be too cold, too damp, too 

 uncertain in England to allow of the introduction of the 

 proposed culture. I cannot conceive or allow that there 

 can exist any sensible difference between the climate of 

 the southern counties of England and that of Picardy 



and Flanders. I do not take notice of Prussia and even 

 Russia, where tobacco is grown. I believe that the 

 general climate in .Southern England is more genial than 

 in the countries across the Channel, and 1 feel confident 

 that in the said southern counties of England and in Ire- 

 land tobacco could be advantageously grown. I recall 

 my former statement that the plant is only on the ground 

 from June to September : cold winters, early frosts, and 

 November fogs have naught to do with the question." 

 Tiie author does not appear to take into account the 

 comparative coolness of the summer months in England, 

 which has always prevented the successful growth of 

 maize, vines, and probably tobacco also. This very 

 readable little book, with its unstudied side-lights upon 

 French rural life, and its pleasant style, may be recom- 

 mended without any hesitation to the reading public. 

 John Wrightson 



Marion's Practical Guide to Photograpliy. (London : 



Marion and Co., 1886.) 

 Here we have a very good book, which contains all 

 necessary information and useful hints for those who are 

 practising the art of photography. The whole process is 

 gone through in a very clear and easy way. Extra chap- 

 ters are given on different parts of the subject, such as 

 photographic optics, re-touching, portraiture, &c. On 

 p. 95 a table of exposures is added, preceded by e.\plana- 

 tions. taking into consideration all the variations of scenes 

 and subjects which the amateur is likely to come across. 

 The manufacturers deserve great credit for publishing 

 a book in which the best way of using their apparatus is 

 described ; a book published under such conditions 

 ought to be truly practical, and one would think 

 that the manufacturer of bad apparatus would not be too 

 anxious to teach his customers how to find it out. 

 Lecture Notes and Problems on Sound, Liqht, and Heat. 



By Charles Bird, B.A., F.G.S. (London ; Relfe Bros., 



1886.) 

 For students who are attending lectures on these sub- 

 jects this book will be very useful, as it contains the chief 

 fundamental formulae, set out in a very clear manner, and 

 it is very compact, capable of being put into one's pocket 

 without inconvenience. 

 Bicycles and Tricycles for the Year i885. By H. H. 



Griffin, London Athletic Club. (London : L. Upcott 



Gill, 1S86.) 

 Now that cycling has become so general, and conse- 

 quently the cycle industry increased so largely, a book 

 on the subject will doubtless be most welcome. We 

 have here one which gives a good description, and in 

 many cases a woodcut, of every known make, with the 

 exception, perhaps, of one or two very new patterns 

 which have been introduced very recently. We need 

 not enter into the details from the scientific point of view, 

 as they have been previously described (NATURE, vol. 

 xxxiii. p. 132). A description of different varieties of 

 bells, lamps, &c., is also given. Great pains seem to 

 have been taken by the author to bring the book up to 

 date, and to give an accurate account ; each machine, 

 as he tells us, having been examined by himself 



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 correspo7id -iviih the writers of rejected manu- 

 scripts. No notice is taken of anonymous communications. 



[ The Editor urgently requests correspondents to keep their letters 

 as short as possible. The pressure on his space is so great 

 that it is impassible otherwise to insure the appearance even 

 of communications containing interesting and novel facts.^ 



Extension of the Corona 



In reference to the failure of observers at the late eclipse to 

 note any such extension of the corona as was seen in 1S78, I 



