AUGUST 7, 1902 | 
NATURE 34 
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LETTERS TO THE EDITOR. 
(The Editor does not hold himself responsible for opinions ex- 
pressed by his correspondents. Neither can he undertake 
to return, or to correspond with the writers of, rejected 
manuscripts intended for this or any other part of NATURB. 
No notice 2s taken of anonymous communications.) 
A Simple Telephonic Receiver for Wireless 
Telegraphy. 
WHILST engaged in some testing experiments with an instal- 
lation for wireless telegraphy (Popoff system) between the Hook 
of Holland and the Government lightship, lying at a distance 
of 16 km. from shore, it occurred to me to try telephonic 
communication. As the necessary apparatus, now constructed 
by different companies, could not be procured without much 
delay, I made myself a most simple arrangement, yet yielding 
excellent results, an account of which may interest those occupied 
in similar experiments. 
I fixed two parallel pieces of carbon (as used in an ordinary 
arc lamp) having a length of 5 cm. ona square piece of wood, 
and made with it a circuit including a couple of dry elements 
(small size) and an Ader telephone ; the circuit was completed by 
placing three or four common sewing needles loosely in trans- 
versal direction on the carbon rods. The apparatus is ready 
for use when the insulated wire of the signal mast (antenna) 
is joined to one carbon and the other is connected to the earth 
conductor. The letters from the Morse alphabet are very dis- 
tinctly heard by this most simple device as shorter and longer 
taps in the telephone, and at the given distance the telegrams 
were easily read by sound, by a trained operator, as they were 
sent from the ship, and inore quickly, of course, than they 
could be delivered by the usual coherer arrangement combined 
to the Morse writer; besides, it does not require special care 
to keep it in working condition. Yet it is sensitive enough to 
make audible the peculiar noise which accompanies the motion 
of the interrupter combined with the induction coil when it is 
operated by hand to produce the spark. 
I believe that such a receiver may prove very useful for tem- 
porary installations of wireless telegraphy, as any one may 
carry it, along with all its accessories, in his pocket and put it 
at once in action when an insulated wire can be fixed to some 
elevated post, earth connections being always at hand. 
I also investigated this arrangement in my laboratory with 
the view to ascertain whether it is really auto-decohering, as has 
been claimed recently for circuits where a telephone is used 
and carbon as coherer substance. Indeed, it seems that no 
tapping or any other arrangement is required to keep the tele- 
phone in good receiving condition. But when I substituted a 
sensible aperiodic galvanometer (Weston’s construction) for the 
telephone, and operated with a small induction coil and Leyden 
jar (spark 3 mm.) in an’adjacent room, every discharge produced 
a deflection of the needle, which did not return to its former 
position, unless a slight tapping was applied near the 
carbons, otherwise each new spark increased the deflection 
obtained by the former. It may be that the self-induction of 
the coil of the telephone is sufficient for decohering, which 
factor is not so active when a galvanometer is substituted. 
I examined other substances than the steel needles, namely, 
copper, nickel, platinum, carbon, this also in powder (as 
used in the Mixtand Genest telephone), and they all gave the 
same result, and this was obtained in. the best way when, before 
the sparking of the coil, the transverse wire, by slightly tapping, 
had obtained a contact sufficient to transmit a small portion of 
the circuit current. But I observed that sometimes with platinum, 
and also with carbon, the deflection was reduced to zero, when 
the sparks set in, indicating that the resistance was increased 
by the electric waves, instead of diminishing, as was usually the 
case. 
I found that a certain pressure exerted on the transverse wire, 
lying on the carbons, did not prevent the influence of the 
electric waves on the contact surfaces. When a load of 1°5 kg. 
and even of 5 kg. was placed on the needles (protected from 
immediately touching them bya glass plate), the deflection of the 
galvanometer set as well in and the telephone answered as dis- 
unctly to the sparks, produced in another room, as before. 
It is obvious that the described arrangement proves also to 
be a very delicate microphone, but a slight pressure applied in 
the same way on the transverse wires makes it directly insen- 
sible to sound impulses, as was to be expected. 
The Hague, July. L. BLEEKRODE. 
NO. 1710, VOL. 66] 
The Future of the Victoria University. 
PROF. SCHUSTER(p. 319) does not challenge the accuracy of my 
statements and I have nothing to alterin them. I have enjoyed 
reading his playful comments, but I have no desire to enter 
upon a mere dialectic contest with him, especially if it is to be 
fought with dynamical metaphors. I only wish now to disavow 
the predilection for federal universities, which Prof. Schuster 
artfully attributes to me. I have certainly acquired belief in 
one existing federal university which includes Lancashire and 
Yorkshire, but if that ‘‘experiment” is to fail, I do not see 
that I should necessarily favour another of the same kind. I 
must therefore decline with thanks the consolation that is offered 
me in the contingent possibility of my being able to take part in 
a federal university for Yorkshire. The immediate need of 
those who are or may be charged with university organisation 
seems to me to be an authoritative and impartial pronouncement 
on the causes which are alleged to warrant the disruption of the 
Victoria University. This is what I await before agreeing to 
any fresh experiment. ARTHUR SMITHELLS. 
August I. 
M. Faye and the Paris Observatory. 
I THINK the addition of the following to the excellent article 
on Hervé Faye in NATURE of July 17 (p. 277) is of interest. I 
had the facts from Le Verrier and Faye; they have not been 
reported in the speeches delivered, and should not be lost to 
history. 
It is known that one of the great things done by Le Verrier 
was the creation of the Central Bureau of Meteorology, as part 
of the Paris Observatory. When the celebrated astronomer 
was dismissed, in 1870, by the Emperor, no change took place 
in the organisation of this establishment. When Le Verrier was 
recalled, in 1872, after Delaunay’s accidental death, he filled, as 
in former times, the double position of head of French astro- 
nomy and of meteorology. But he was told that steps were 
being taken by the Administration to form a Central Bureau, 
independent of the Observatory, when he should have breathed 
his last. This idea grieved Le Verrier ; he complained bitterly 
of it to his friends and to the Academy. 
When Le Verrier died, M. Yvon Villarceau was appointed 
intermediate director, and filled this office for some months. 
M. Bardoux, a member of the Senate, sent a message to the 
Academy of Sciences asking its opinion on the idea of creating 
an independent ‘‘ Météorologie.” The question was warmly 
discussed in secret session, and M. Faye, like many others, 
raised objections. The Academy accepted their opinion, 
and answered in the negative to the official proposition. As 
the advice of the Academy was not binding, M. Bardoux had 
a right to disregard it, which he did, The reputation of M. 
Faye was such that he was generally considered as being the 
only possible successor of Le Verrier. M. Bardoux advised 
M. Faye to accept the directorship of French astronomy, as 
meteorology would henceforth forma separate department. M. 
Faye thanked M. Bardoux, but declined under such conditions. 
WILFRED DE FONVIELLE. 
Electrical Resistance of Iron at very Low 
Temperatures, 
OwING to the kindness of Dr. M. W. Travers in providing 
me with some liquid hydrogen, I have recently been able to 
observe the resistance of a specimen of iron wire at a tempera- 
ture of about 20° absolute. The specimen was the same that 
had been used in previous experiments on resistance between 
1100’ and ~—200°, and the result of continuing the resistance- 
temperature curve is of considerable interest. In two papers on 
this subject Profs. Fleming and Dewar reach the conclusion that 
the resistance of pure metals tends to vanish at the absolute 
zero, but that the presence of impurity in the specimen reduces 
the rate of decrease of resistance with temperature, and that 
this behaviour may even afford a test of the purity of a conductor. 
This bears out a remark made by M. Edmund Van Aubel 
(Annales de Chimie et de Physique, 1899) that the purity of 
bismuth can be gauged by the variation of its electrical resist- 
ance between 0° and 30°. 
The temperature coefficient of bismuth is abnormal when the 
element is in certain physical conditions, its resistance increasing 
with fall of temperature in more than one position over the 
range indicated, a behaviour which is less surprising if bismuth 
really contains a small percentage of polonium. An observation 
