June 25, 1896] 



NA TURE 



"The Old Light and the New." 

 VorR reviewer expressed an opinion, and makes two state- 

 ments, and the six lines comprise his review of my book. The 

 opinion, being on a matter of business, may be right or may be 

 wrong. The statements are supposed tn relate to fact ; but 

 they must be the outcome of hasty rtadint;, for the " large 

 I portion of the book, dealing with theories of the natural colours 

 ' of bodies," cannot surely be spoken of as " jiadding" in a work 

 5 whose sub-title is " The Chemistry of Colour," and one of 

 whose objects is to show that the Rontgen rays and matter 

 yield "invisible" colour which conforms to the same laws as 

 " visible " colour. Nor do I think it correct to call information 

 on the X-rays "sketchy" because it happens to be concise. 



William Ackkovd. 



In my brief criticism of Mr. Ackroyd's book, I did not intend 

 to suggest that the whole of the section on natural colours was 

 "padding." My meaning would, perhaps, have been clearer 

 had I written, "a large portion of that part of the book which 

 deals with theories ol the natural colour of bodies is nothing 

 more than padding." The forty pages which comprise the 

 chapter on " The Chemistry of Colour," contain the substance 

 of a lecture delivered before the Society of Dyers and Colourists, 

 and is so full of tabular details, while the remainder of the book 

 is of a very elemenlar)' character, that it certainly gives the 

 impression of having been included more to increase the bulk 

 than on account of suitability. Y<5iR Reviewer. 



" The Reminiscences of a Yorkshire Naturalist." 

 The brevity of the reference, on page 205 of "The 

 Reminiscences of a Yorkshire JJaturalist," by Ur. W. C. William- 

 son, to the memoir in the Aiiiiales des Siicmcs Natnre/les, may 

 give rise to misconception. Prof. Hartog's share in this work 

 was by no means that of a mere translator, although his 

 exceptional ability as a French scholar was of essential service. 

 I lis collaboration extended to the substance as well as the form 

 of the memoir, and he was always fully recognised by Dr. 

 Williamson as its joint author. .\. C. Williamson. 



Post-Graduate Study in London. 



Could you inform a graduate in science of London University 

 whether there is any place in London where he could attend 

 post-graduate and research courses of study in botany ? He is 

 engaged as science master in a large public day-school, but is 

 anxious to study botany in his spare time. Any information 

 will greatly oblige. " PUTHOS." 



June 14. 



LORD KELVIN'S JUBILEE. 



OUR summary in last week's issue of the proceedings 

 at Lord Kelvin's jubilee celebration gives only a 

 faint idea of the completeness and success with which 

 every part of the festival was carried out, or of the en- 

 thusiasm which characterised what was the world's tribute 

 of admiration to the achievements and personal qualities 

 of a truly great man. The list of delegates and visitors 

 which we give on pp. 174-5 "''1 con\ey some idea of the 

 unanimity with which science and learning throughout 

 the world have done honour to one who, besides advanc- 

 ing pure science in a remarkable degree by his own 

 abstract researches, has not disdained to apply his great 

 knowledge of scientific principles to the construction of 

 apparatus and appliances which have promoted peace 

 and good will among men and aided commerce by placing 

 continents in telegraphic communication, by improv- 

 ing and facilitating navigation, and last but not least, 

 diminished the perils to which those who sail the seas are 

 exposed. .-Y great physical mathematician, a physicist to 

 whom physical principles are intuiti\e, an engineer whom 

 engineers have united to honour as one of the greatest of 

 therasehes. Lord Kelvin has many >cientific interests, 

 and there is no department of science which is not the 

 larger and richer for his work. 



The opening meeting of the celebration was the con- 

 versazione on Monday evening at the University. The 



NO. 1 39 1. VOL. 54J 



guests were received by the Senatus Academicus, and 

 the members of the Corporation of the City of Glasgow- 

 headed by Lord Provost Sir James Bell, in the Randolph 

 Hall, which forms a "Fore Hall" or vestibule for the 

 magnificent Bute Hall in which the high ceremonies of 

 the University are held. In the Bute Hall, a little 

 beyond the entrance and to the left, chairs were set for 

 Lord and Lady Kelvin, who stood receiving the individual 

 congratulations of the multitude of distinguished visitors. 

 After thus paying their respects to the hero of the 

 occasion, the guests passed on to meet one another, 

 to renew- acquaintanceships, to look at the treasures of 

 the museum, and to inspect the splendid collection of 

 instruments, diplomas, and medals which had been 

 arranged to illustrate Lord Kelvin's researches and 

 inventions, and the honours he has received. In this 

 e.xhibition were many things of great interest, and we 

 will not attempt even their enumeration. To give an 

 adequate account of the instruments alone wOuld require 

 several numbers of NATURE, while the diplomas, mostly 

 in Latin and of extraordinary distinction, represented 

 the honour in which Lord Kelvin is held by the learned 

 societies at home and abroad. Beginning with the certifi- 

 cate of the Bishop of Ely approving the appointment of 

 William Thomson, B.A., as a Fellow of Peterhouse, they 

 ended with the credentials of Sir William Thomson or Lord 

 Kelvin's election as member of every one of the most 

 distinguished scientific societies of the world, and in- 

 cluded the letters of the Perpetual Secretary announcing, 

 first. Lord Kelvin's election as Corresponding Member, 

 next, as Foreign .-Yssociate of the Institute of France, 

 and the announcement of his appointment as Grand 

 Officicr of the Legion of Honour. 



The part played by the telegraph in the conver- 

 sazione formed an exceedingly interesting part of the 

 proceedings. The chief Cable Companies — the Anglo- 

 American, the Commercial, the Eastern, and the Brazilian 

 .Submarine — sent congratulations, and instruments were 

 arranged in the Liljrary Hall whereby messages could 

 be received from all parts of the world during the soiree. 

 The .A-nglo-American Company's message may here be 

 quoted, as it gives in a few words that credit for rendering 

 by his instruments submarine telegraphy practically pos- 

 sible, which is Lord Kelvin's due, and that by a large 

 portion of the commercial public that carries on business 

 by means of cable communication is either unknown or 

 apparently forgotten. 



In 185S Professor William Thomson took out his first patent 

 for a system of working long cables, and for instruments (including 

 the mirror-galvanometer) calculated for producing a high rate of 

 transmission. In the Atlantic expedition of 1S58 Professor 

 William Thomson, at that time one of the directors of the 

 Atlantic Telegraph Co., at the request of his brother directors, 

 took upon himself the duties of electrician on board H.M S. 

 Jgarucinnoii, which had been placed at the disposal of the com- 

 pany lor the laying of the first Atlantic cable ; and when the 

 cable had been laid, it was Professor William Thomson's inven- 

 tions and genius which caused a sufficient number of messages to 

 be transmitted to demonstrate the practicability of Atlantic tele- 

 graphy, thus contributing most materially to the present success. 



Our readers will remember that the theoretical solution 

 of the problern of telegraph signalling by Lord Kelvin 

 consisted in showing that the '■ retardation " of a signal 

 increases in direct proportion to the square of the 

 length of the cable supposed of a given pattern ; and that 

 therefore it was only possible by using receiving instru- 

 ments for surpassing in delicacy the most sensitive of 

 land instruments that intelligible signals could be obtained 

 at all. There can be no manner of doubt that it was the 

 tremendous battery power used to actuate the primitive 

 receiving instruments that ruined the cable first laid, and 

 brought temporary disaster to the promoters. The 

 mirror-galvanometer with its needle and minor of a grain 

 or two hung by a single fibre of silk, and its long mass- 



