12 



NATURE 



\_May 3, 1883 



5. Essay on the constitution of the solar system, 

 in which M. Roche attempted to develop the beauti- 

 ful cosmogonie theory of Laplace, giving precision to 

 certain points and modifying it in others. M. Roche was 

 a Corresponding Member of the Academy of Sciences in 

 the Section of Astronomy, and had been nominated as 

 a candidate for the place vacant by the death of M. 

 Liouv.ille. 



THE LATE MR. IV. A. FORBES 



lyTR. WILLIAM ALEXANDER FORBES, Fellow 

 ■*•"■*■ of St. John's College, Cambridge, Prosector to the 

 Zoological Society of London, and Lecturer on Compara- 

 tive Anatomy to Charing Cross Hospital, whose untimely 

 death on the Niger we announced last week, was born at 

 Cheltenham on June 24, 1855, tne second son of Mr. J. 

 S. Forbes, the well-known railway director. He was 

 educated at Kensington School and Winchester College, 

 which he entered at the early age of eleven. On leaving 

 Winchester in 1872, Forbes passed a year at Aix-la- 

 Chapelle studying German, and then became a student 

 of the University of Edinburgh, where he pursued the 

 regular medical course, paying special attention to zoology 

 and botany, and commencing collections of insects and 

 plants. In 1875 Forbes transferred his residence to 

 London, and entered himself as a student of London 

 University with the idea of taking a medical degree in 

 the metropolis. Here he became quickly intimate with 

 other zoologists, who were very soon attracted by the 

 astounding general knowledge of zoology and the acute 

 intelligence of one so young. By the advice of the late 

 Prof. Garrod and other friends Mr. Forbes was induced 

 in October, 1876, to leave London and to become an 

 undergraduate of St. John's College, Cambridge, where 

 he was subsequently elected Scholar, and took his B.A. 

 degree with a First Class in the Natural Sciences Tripos 

 in 1879. The post of Prosector to the Zoological Society 

 of London having become vacant in October, 1879, by 

 the lamented death of Prof. Garrod, Mr. Forbes was ap- 

 pointed {omnium consensu) to that office in the January 

 following. Indeed he had been designated by Garrod on 

 his deathbed as his most obvious and proper successor, 

 and had been appointed his literary executor. 



Mr. Forbes entered upon the duties of his office with 

 characteristic energy, and during the three following 

 sessions of the Zoological Society brought before the 

 scientific meetings a series of most interesting and valu- 

 able communications derived from his studies of the 

 animals that came under his examination. He had a 

 happy knack of putting forward abstruse points of 

 anatomy in an understandable form, and especially 

 directed himself to the muscular structure and voice- 

 organs of birds, in continuation of the researches of his 

 predecessor Garrod on the same subjects. I n the summer 

 of 1880 Mr. Forbes made a short excursion to the forests 

 of Pernambuco, Brazil, of which he published an account 

 in the Ibis for i88r, and in the following year passed his 

 holiday in the United States, in order to make the 

 acquaintance of his American brethren in science and 

 their collections. In July, 1S82, he left England on what 

 promised to be a splendid opportunity of visiting the 

 eastern tropics with every advantage and without much 

 risk. Detained at Shonga — a station some 400 miles up 

 the Niger below Rebba — by the breaking down of his 

 communications, Mr. Forbes fell a victim to dysentery on 

 January 14 last, thus adding another name to the long list 

 of martyrs of science in that deservedly dreaded climate. 



Mr. Forbes's published works consist chiefly of papers 

 in the Proceedings of the Zoological Society and the Ibis, 

 altogether about sixty in number. He was editor of the 

 memorial volume of collected scientific papers of his pre- 

 decessor Garrod, and just before he left England in July 

 last had finished the last sheets of an excellent memoir 



on the anatomy of the petrels — since published in the 

 "Zoology of the Challenger Expedition." This piece of 

 work was originally undertaken by Garrod, but had been 

 left almost uncommenced at the decease of the latter. 



Of Forbes's private qualities as a most efficient and 

 ready fellow-worker, a most charming companion and a 

 most sincere friend, the writer is able to testify, not only 

 from personal experience, but also from the universal 

 regret expressed at the unhappy end of so promising 

 a naturalist. P. L. S. 



S 1 



RECENT INFLUENCE-MACHINES 



EVERAL modified types of influence-machine have 

 recently been brought before the public, and as they 

 are both cheaper and more efficient than the older forms 

 of Topler, Holtz, and Bertsch, will probably find general 

 acceptance. Of the newer forms, those of Voss and of 

 Wimshurst are illustrated in the accompanying cuts. 



In the Voss machine, which may be regarded as a 

 modified Topler machine, there are two disks of varnished 

 glass, one stationary, the other rotating in front of it on 

 an axis which passes through a central hole through the 

 fixed disk. A pair of pulleys with a strap provide the 

 rapid movement necessary. At the back of the fixed disk 

 are fixed two armatures or inductors of varnished pape^ 



Fig. 1. — Voss 



nfluence-Mr.chine. 



with a narrower central band of tinfoil. These armatures 

 are connected on the right and left respectively with two 

 metal clamps which nip on to the edge of the disk and 

 turn round in front of the front plate, each being provided 

 at this part with a little metallic brush. Upon the front 

 of the rotating plate are fastened six or eight metal 

 buttons at equal intervals. These buttons are touched as 

 they rotate by the metallic brushes. Nearly perpendicu- 

 lar, and in front of the front disk, is a brass rod, which 

 need not be insulated, also furnished with spikes at each 

 end, and with a little metallic brush to touch the buttons 

 of the rotating plate. The action of the machine is as 

 follows : — If a small charge of electricity — say a positive 

 charge- be imparted to one armature —say that on the left 

 — the buttons astheymovepastwillbe acted on inductively, 

 and if, while thus under the inductive influence of the positive 

 charge, they are momentarily touched by an uninsulated 

 conductor, they will pass on electrified with a charge of the 

 opposite sign. If the front plate rotates in the clockwise 

 direction, each button as it moves through its highest 

 position towards the right will thus acquire a small 

 negative charge which will be given up on arriving at the 

 right side, the projecting arm conveying the charge to 

 the armature at the back. But as the button passes on 

 downwards it will be influenced inductively by the arma- 

 ture behind it, and when touched by the lower end of the 

 vertical conductor, will assume a positive electrification. 



