Fan. 18, 1883] 
found favour with the public are the well-known inven- 
tions of Brush and Weston. Though the clutch device is 
in itself simple and efficient, the difficulty which has 
beset the action of such lamps has been that of arranging 
suitable electric mechanism to work the clutch. In 
Hart’s lamp an electro-magnet through the coils of which 
the main current passed on its way to the lamp, lifted the 
clutch, and again released it when the increasing resist- 
ance of the arc interfered with the strength of the cur- 
rent. In the lamps of Weston and of Brush a much 
more complicated arrangement was adopted, the magnets 
which worked the clutch being in both these patterns of 
lamp wound “ differentially,” that is to say, with a coil of 
fine wire connected as a shunt to the lamp, acting in 
opposition to another coil of thick wire through which the 
main current flowed. This differential principle was 
originally applied in the Siemens’ lamp, wherein, however, 
no clutch was used. In the Pilsen lamp, and in many 
others, combinations of shunt magnets and main: circuit 
magnets have been similarly applied. The lamp which 
we illustrate in the figure, the invention of Mr. Charles 
Lever, of Manchester, is a clutch lamp, but of remarkably 
simple, yet efficient construction. And as it possesses 
sundry points worthy of notice from a scientific aspect, 
we will briefly describe it. The upper carbon is clamped 
ina holder or carbon rod ¢, which consists of a tube of 
brass sliding smoothly through the upper framework of 
the lamp. Fitting accurately, but not tightly to it, is a 
brass washer, or collar, B, which is supported from below 
or on one side by an adjustible screw, G, and on the other by 
a metal piece, I, projecting from the jointed framework 
NATURE 
mT 
below. This framework is held up by a spiral spring, D, 
which, when the lamp is not in action, keeps the piece, 1, 
pressed up under the washer, B, and tilts it. When thus 
tilted it clutches the carbon-holder, C, and raises it. 
Attached to the under-side of the jointed framework 
alluded to is an iron bar, A, bearing two broad-ended 
iron screws, J, below which, again, are seen the two limbs 
of an electro-magnet, FF, with the poles upward. This 
electro-magnet is wound with fine wire, and connected 
asa shunt to the lamp. Now, as described above, when 
the lamp is not in action, the carbons are held apart by a 
spring. When the current is turned on it must therefore 
pass through the shunt magnet, which immediately attracts 
the bar, A, lowers the piece, I, releases the clutch-washer, 
B. The upper carbon then falls, and the current is 
diverted from the shunt-magnet to the lamp itself, passing 
through the carbons. But when this takes place, the 
spring, D, being no longer opposed, draws up the frame- 
work, and picks up the clutch, thus raising the upper 
carbon through the space requisite for the production of 
the arc. A more simple or efficient mechanism would be 
difficult to devise; and its action is extremely regular 
and steady in practice. 
NOTES 
Pror. Hux Ley has been appointed to deliver the Rede 
Lecture (Cambridge) this year. 
Mr. G. H. Darwin, M.A., F.R.S., has been elected to the 
Plumian Professorship of Astronomy and Experimental Philo- 
sophy at the University of Cambridge, vacant by the death of 
the Kev. James Challis. This was the first election to a profes- 
sorship since the approval of the new University Statutes by 
Her Majesty in Council. By the new statutes the election to 
certain professorships is vested in a Board nominated by the 
Special and General Boards of Studies and by the Council of 
the Senate, the persons so nominated being elected by the 
Senate. The members of the Board appointed to elect to the 
Plumwian Professorship are the Vice-Chancellor, Prof. H. J. S. 
Smith, of Oxford, Mr. W. H. M. Christie, the Astronomer- 
Royal, Mr. W. Spottiswoode, President of the Royal Society ; 
Profes-ors Adams, Stokes, Cayley ; Dr. Ferrers, Master of Gon- 
ville and Caius ; and Mr. Isaac Todhunter, of St. John’s. 
THE subscription for the Darwin Memorial has awakened so 
much enthusiasm in Sweden that the local committee there 
formed has received subscriptions from no less than 1400 per- 
sons, including ‘‘all sorts of people,” writes Prof. Loven in a 
letter to the English Committee, ‘‘ from the bishop to the seam- 
stress,” the sums varying from five pounds to twopence. The 
English Committee, which has its head-quarters at the Royal 
Society, London, has now rec-ived (inclusive of subscriptions 
from abroad), 4000/., but the number of subscribers in the 
United Kingdom is only about 600, From this it would seem 
that an interest in science is not nearly so widely spread in 
Britain as it is in the more thinly peopled land of Sweden. 
In announcing the death of Mr. Darwin to the American 
Philosophical Society at iis meeting on April 21, 1882, Dr. Le 
Conte stated the general bearing of Darwinism in a striking and 
unusual way :—‘'To no man more than to Darwin does the 
present age owe as much, for the gradual reception of the modern 
method of close observation over the scholastic or @ friort 
formule, which, up to a brief period, affected all biological 
investigations, To him, above all men, we owe the recurrence 
to the old Aryan doctrine of evolution (though in those ancient 
times promulgated under the guise of inspiration) as preferable, 
by reasonable demonstration, to the Semitic views, which have 
prevailed to within a few years, and are still acceptable to a 
large number of well-minded but unthinking men, The doctrine 
