57! 



NA TURE 



\_April 



protean : our faith in this measure is rudely shaken by 

 the statements on pp. 104-5. There are many interest- 

 ing statements in Chapter XII., but one finds it difficult 

 to discover why the heading should be "Chemical 

 Affinity." 



The time is surely past when we are to expect the 

 chemical student to be content with a sketchy outline of 

 such subjects as affinity and thermo-chemistry. If these 

 is are really parts of the science of chemistry — and 

 surely they are all-important parts — let them be dealt with 

 as such, and not thrust into a corner and treated so that 

 the student is ready to conclude that, if he is able to repeat 

 the properties of the elements and their compounds, he 

 must of necessity be a chemist. The real science of 

 chemistry is something more than a string of disconnected 

 facts and a few mutually independent hypotheses. 



We cannot but think that, had the authors of this book 

 cut out most of the graphic formula;, been content to use 

 the notation adopted by other chemists, and carefully 

 considered, digested, and arranged the materials they 

 have brought together in the first nineteen chapters, they 

 would have produced a much better and a much more 

 scientific treatise. M. M. P. Mum 



LETTERS TO THE EDITOR 



[ The Editor does not hold hi;nsc!J responsible for opinions express ed 

 by his correspondents. Neither can he undertake to reiui «, 

 or to correspond with the writers of, rejected manuscripts. 

 No notice is taken of anonymous communications. 



[The Editor urgently requests correspondents to keep their letters 

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

 that it is impossible otherwise to insure the appearance even 

 ■nmunications containing interesting and novel facts.} 



Mr. Lowne on the Morphology of Insects' Eyes 



(1) It is, I imagine, sufficiently obvious that I was not at 

 liberty to state in my previous letter the circumstances connected 

 with the action of the Royal Society in regard to Mr. Lowne 1 

 paper, now inaccurately related by him. 



It is also clearly impossible that I should take any notice of 

 Mr. Lowne's letter in your journal of April 9 (p. 528) beyond 

 .expressing my surprise that he should suppose that I have had 

 any personal feeling in regard to him or his work, and my regret 

 that he should accuse Prof. Schafer, Dr. Hickson, the Royal 

 Society, and the Cambridge histologists of ill-treating him in 

 various ways. 



(2) I would beg to assure my friend Dr. Romanes that he is 

 mistaken if he imagines that I intend to publicly discuss the 

 affairs of the Linnean Society with him either here or elsewhere. 

 At the same time I consider that I am at liberty to express my 



m nt as to the scientific value of a paper published by the 

 Linnean Society, and that neither he nor the author of the paper 

 are entitled to object to my discharging what I conceive to be 

 my duty in this respect. E. Ray Lankestek 



II, Wellington Mansions, N.YV. 



Abnormal Season in the Niger Delta 

 As you are aware the waters of the Nile are at present 

 abnormally low, and having just received a letter from the 

 Niger, I thought it might interest you to learn that the season 

 is abnormal also there. My correspondent, who has an experi- 

 ence of many years on the river, states : — 



"We have had the most extraordinary weather since the 

 commencement of the year — heaps of rain up to this present 

 during both months (January and February), and yesterday one 

 of the Worst tornadoes I have ever seen, and that from the due 

 .north ; usually the bad ones come about Christmas from the 

 south-east. 1 never saw rain, up to the present, after Christmas 

 during the first three months of the year, which are the unhealthy 

 ones. These months are this year so far fairly healthy, although 

 the falling of so great a river as the Niger must wash di 



mass of filth, not so much from the towns on the banks as from 

 the hundred small and large villages and towns up all the creeks 

 or tributaries along its banks." 



I have asked if any barometer observations are made, and if I 

 could have a return of them for the past Year. 



J. P. O'Reilly 

 Royal College of Science for Ireland, Stephen's 

 en, Dublin, April 16 



Tardy Justice 



You well advocate the establishment of a well-endowed scien- 

 tific University in London. Perhaps, however, London is like 

 a mass of dough which needs leaven. Why should not the Cor- 

 poration of the City of London be that leaven ? Perhaps, how- 

 ever, the Corporation needs that some one should employ a 

 yeast-germ in order to start its fermentation. Or, if it be lawful 

 to compare that august body to a pump, perhaps a handle is 

 necessary which some one mny work. Why should not the 

 tin, or the handle, be found in Gresham College? 



April 17 Z. 



A Query 



I WONDER if any of your readers could suggest a material 

 which would fulfil the following requirements : — (1) Great cheap- 

 ness ; (2) capability of being readily cast, or moulded, into 

 simple shapes with no delicacy of detail ; (3) not very brittle ; 

 (4) not fusible under a temperature of too" F. It should also 

 afford a surface which could be readily painted, and it should not 

 be too heavy, a specific gravity not much in excess of water being 

 the best. India-rubber I find answers all requirements suffi- 

 ciently well, except that it is much too expensive a material. 



April 17 M. X. 



The Use of Artificial Teeth by the Ancients 



Tii is is not a new discovery, as stated in Cosmos (see Natt i; E, 

 April 16, p. 564). Cicero, De Legib. II., 24, quotes a law from 

 the Twelve Tables forbidding the combustion or burial of costly 

 golden articles, but allowing an exception in favour of "teeth 

 fastened with gold " (Quoi auro denies vincti cscunt, &*c). 



Heidelberg, Germany, April iS O. S. 



Far-Sightedness 



A PANORAMA of the Alps, as seen from the Piz Langard in 

 the Engadine, used to be sold, upon which Mont Blanc was 

 figured, though some 3° distant. On a remarkably clear day 

 this was pointed out to me, and I have no reason to doubt that 

 I actually saw Mont Blanc at that distance. One morning I 

 was walking on the terrace in front of Mr. Leland Cossart's 

 house in Madeira, at an elevation of close upon 2000 feet above 

 the sea, when the conversation turned on far-sightedness, and I 

 pointed out two specks on the horizon as vessels. This they 

 proved to be, when my friend informed me that no vessels had 

 before been made out on the horizon from that position, even 

 with the telescope. J. Stariue Gardner 



7, Darner Terrace, Chelsea, April 17 



A IMS AXD METHODS OF THE TEA CHI XG 

 OF PHYSICS 1 



THE United States Bureau of Education has recently 

 employed Prof. Charles K. Wead, A.M., Acting 

 Professor of Physics at the University of Michigan, to 

 draw up a set of inquiries respecting the teaching of 

 physics and to collate and discuss the answers received. 

 The results of his labours are now before us in a rather 

 unusually lengthy circular issued by the Bureau. They 

 are drawn from seventy replies to a set of questions sent 

 to a selection made by the Commissioner of Education 

 of masters of schools of various grades in the United 

 States, compared also with information gathered from 

 England and other countries. A table at the end showing 

 as clearly as can be done in a word or two under each 

 heading the tendency of each answer, makes it easy to 



1 " Circular of Information," No. 7, 1SS4. of the U.S. bureau of Educa- 

 tion. (Washington. 1884.) 



