3i8 



NATURE 



[Feb. 2, I 



The first of these stories is related in very circumstantial terms, 

 but without any authority being given for it. It is said that a 

 Fellow of the Geological Society offered a certain paper, which 

 the authorities of the Society refused ; and it is asserted that the 

 reason of their refusal was that the paper "was not orthodox," 

 and "they probably smelt heresy." Now the Duke of Argyll 

 is well aware that every Fellow of the Geological Society has the 

 right to present papers for reading, and that the responsibility for 

 accepting or refusing papers rests in the first instance with the 

 President ; but he, in the case of exercising his veto, is bound to 

 report the fact, and the reasons for his action, at the next meeting 

 of the Council. The records of the Society show that no such 

 paper was ever offered to it ; that the President never exercised 

 Ms right of veto ; and that the Council never discussed the 

 grounds of the supposed refusal. The Duke of Argyll has been 

 informed of these facts, but he has not yet retracted the very 

 serious charge which he has made affecting the honour and good 

 faith of the President and the other twenty-two members of the 

 Council of the Geological Society. 



In the case of the second story circulated by the Duke of 

 Argyll, the authority is given. The complaint is made that since 

 1862 "advanced geologists" have "i^^nored" views which 

 "tend to dethrone " their own "pet theories." Anyone who 

 chooses to refer to the Philosophical Magazine for 1862 will 

 see that the "pet theories" in question are those relating to the 

 antiquity of man; that the "advanced geologists" implicated 

 in the charge must have been the late Sir Charles Lyell, Prof. 

 Prestwich, and those who have followed up their researches and 

 arguments ; and that the "views " which they "ignored" were 

 the suggestions which I described in my last letter ! 



John W. Judd. 



The Total Eclipse of the Moon of 1888 January 28, as 

 observed at Birr Castle Observatory, Parsonstown. 



The total eclipse of the moon on Saturday last was, like its 

 predecessor in 1884 (see Nature, vol. xxx. p. 589, and Trans, 

 Royal Dublin Society for October 1885), favoured by a very 

 clear sky during the whole time of its progress, so that very 

 extensive observations of the changes of the moon's heat in 

 consequence of the passing over of the earth shadow could be 

 made. The apparatus used was essen'ially the same as that 

 used before ; yet the two old thermopiles had been replaced by 

 two new ones especially made for this occasion by the Earl of 

 Rosse. 



The observations began at yh. 19m. M.T. Greenwich, and 

 were, as much as possible, uninterruptedly continued till I5h. 



45™- 



During this time 638 distinct readings of the galvanometer 

 were obtained, which, when fully reduced, will enable a very 

 satisfactory heat-curve to be drawn. A few preliminary results, 

 reduced to zenith, I communicate at once. 



Galvanometer. 



739 '4 ... ih. lom. before first contact with penumbra. 



663-4 ... 24m. ,, „ „ 



624-1 ... First contact with penumbra. 



252-1 ... ,, shadow. 



34-9 ... 22m. before beginning of total phase. 



30-2 ... 22m. after ,, ,, 



231-9 ... Last contact with shadow. 



545 '6 ... ,, penumbra. 



540'8 ... ih. 34m. after last contact with penumbra. 



From these figures it will be seen — 



(i) That the heat radiated by the moon begins to decrease a 

 considerable time before the first contact with the penumbra. 



(2) That 22m. before the beginning of totality the heat is only 

 47 per cent, of the value obtained ih. 10m. before the first 

 contact with the penumbra. Unfortunately an unforeseen 

 stoppage of the driving-clock prevented the observations from 

 being carried on closer up to and during the total phase. 



(3) That in spite of the rapid fall on approach to totality, the 

 heat, after the last contact with the penumbra, does not at once 

 increase to anything like the value observed at corresponding 

 times before the first contact. 



It is worth remarking that points 2 and 3 are confirmatory of 

 the results arrived at in 1884. Otto Boedicker. 



Birr Castle Observatory, Parsonstown, January 30. 



" Elementary Chemistry," and " Practical Chemistry." 



I CRAVE leave from the Editor for space in which to reply, on 

 my own behalf and on that of my fellow-authors Messrs. Slater 

 and Carnegie, to the charges brought by " H. E. A." in 

 Nature of January 19 (p. 265) against our method of teaching 

 chemistry. At the outset I thank " H. E. A. " for the patience 

 which, as he publicly announces, he has shown in waiting for the 

 publication of these books, and I condole with him in his dis- 

 appointment. Like him, I too am waiting patiently ; I trust my 

 disappointment will be less bitter. 



One of the important points in our plan of chemical teaching 

 is the connection of the work in the laboratory with the student's 

 reading and lecture-work. To emphasize this connection, and to 

 make our course run fairly smoothly, we have published two 

 books, one to be used in the laboratory, the other to be used 

 in the lecture-room and in reading in connection with the whole 

 work of the student. " H. E. A. " acknowledges the advant- 

 ages of this division, but throughout his review he ignores the 

 statement distinctly made by us, that one book is complementarj 

 to the other and that both must be used together. He confines 

 his remarks almost wholly to one of our books, viz. the 

 "Practical Chemistry"; and yet he condemns our system of 

 teaching. On this ground alone I claim that his review is mis- 

 leading and unfair. I go further, and assert that " H. E. A." 

 has condemned our system without acquainting himself with its 

 essential features. He says that "in the earlier part of the 

 ' Practical Chemistry ' Messrs. Muir and Carnegie do not 

 sutficiently bear in mind their own intention, and that much of the 

 matter would find a more fitting place in the companion volume." 

 No one reading this would suppose that almost every experiment 

 used in Chaps. I. to VIII. of the "Practical Chemistry" 

 is also used in Chaps. I. to IX. of the " Elementary 

 Chemistry." Yet this is the case. In one book the 

 experiments are described, along with others, in such 

 terms as allow attention to be concentrated on their results and 

 on the reasoning on these results ; in the other book the experi- 

 ments are described in detail in order that the student may repeat 

 them in the laboratory. In another part of his review " H. E. A." 

 says that most of the subjects dealt with in the third part of the 

 " Elementary Chemistry" " ought never to have been introduced 

 into an ' Elementary Chemistry.' " He has here made a slip : 

 it is the third part of the " Practical Chemistry " which includes 

 subjects not touched on in the other book. This correction in- 

 volves a point of some importance. Although the preface to our 

 " Practical Chemistry " states that the book forms part of a 

 course of elementary chemistry, yet the student who uses 

 both books will see that the course of work laid down in the 

 practical book carries him much beyond the limits of treatment 

 adopted in the other volume. There are numerous direct and 

 indirect indications of this in the book itself, which those for 

 whom the work is intended will not fail to notice. One cannot 

 put the whole of one's book into the preface. I admit that it 

 would have been better had we indicated in the preface to the 

 "Practical Chemistry" that many experiments in Parts II. and 

 III. are difficult to perform,'and require skill and training ; but 

 I assert that the nature of the experiments themselves, the 

 references to the original papers to be read before conducting 

 these experiments, and the suggestions as to other work to be 

 done preparatory to Parts II. and III. respectively, suffice to 

 indicate to the student, although not necessarily to the reviewer, 

 the character of the work described in the later chapters of the 

 "Practical Chemistry." 



Chapter I. of Part III. of the "Practical Chemistry" involves 

 a repetition of some of Stas's determinations of the atomic weight 

 of silver. " H. E. A. " says that this chapter should have been 

 included in Part I., and he adds, "the remaining chapters ougbt 

 never to have been introduced into an ' Elementary Chemistry,' " 

 kindly informing his readers that these chapters are included 

 " because of the senior author's well-known tendency to worship 

 physical constants." I venture to remind " H. E. A." that no 

 election has taken place to the office of supreme pontiff of 

 chemistry. Were that official in existence, I feel inclined to 

 think he would admit that accurate determinations of atomic 

 weights — and " H. E. A." allo-,vs these in the most elementary 

 part of the course — are determinations of constants which have 

 physical as well as chemical meanings. 



" H. E. A. " says that in the " Practical Chemistry" there is 

 an "entire absence of anything approaching to a systematic 

 arrangement." The boldness and baldness of the assertions 

 made by the reviewer encourage me to meet this statement with 



