oo 
he must have been present ’—‘‘ Even now indeed 
telegraphy without wires is possible within a restricted 
radius of a few hundred yards, and some years ago 
I assisted at experiments where messages were trans- 
mitted from one part of a house to another, without 
any intervening wire, by almost the identical means 
here described.” 
That article appeared in 1892, and was an anticipation 
of genius. Too little appreciation is felt to-day for 
the brilliant surmises and careful and conscientious 
observations of a great experimental worker like 
William Crookes; and on some of his researches 
orthodox science still turns its weighty and respectable 
back, 
OTHER METHODS OF DETECTING WAVES. 
In 1889 I had come across the effect of cohesion 
under electric impetus, and employed it to ring a bell 
under the stimulus of the overflow of a Leyden jar, 
as described in my paper to the Institution of Electrical 
Engineers in 1890 (vol. xix. pp. 352-4, where D. E. 
Hughes’s comment on it is also recorded). In 1893 I 
heard —through a demonstration by Dr. Dawson 
Turner at Edinburgh—of Branly’s filings-tube—an 
independent discovery of M. Branly, which really 
constituted an improvement on the first rough coherer 
idea. What I had called a coherer was not this, but 
a needle-point arrangement, or the end of a spiral 
spring touching an aluminium plate, which was and is 
extremely sensitive, but rather unmanageable. 
With a Branly’s filings-tube I made many more 
experiments, developing the subject ; and on the un- 
timely death of Hertz I determined to raise a monument 
to his memory by a lecture at the Royal Institution on 
these experiments (Friday, June 1, 1894), which I 
styled “ The Work of Hertz ””—meaning that it was 
a direct outcome and development inspired by that 
work. I soon found that the title was misleading, so 
that in the next edition I changed it into ‘‘ The Work 
of Hertz and some of his Successors,” and afterwards 
changed it still further into “ Signalling across Space 
without Wires”; for that, of course, is what was being 
* Colonel Crompton now tells me that the experiments to which Crookes 
was probably referring were conducted not by Hughes but by Willoughby 
Smith, who seems to have demonstrated that some sort of communication 
was possible in this way. 
NATURE 

[Marcu 10, 1923 
done in laboratory fashion all the time. The depres- 
sion of a key in one place produced a perceptible 
signal in another—usually the deflection of a spot of 
light—and, as I showed at Oxford, also in 1894, 
employing a Thomson marine speaking galvanometer 
lent me by Alexander Muirhead, 4 momentary depres- 
sion of the key would produce a short signal, a 
continued depression a long signal ;—thus giving an 
equivalent for the dots and dashes of the Morse code 
—if the filings-tube were associated with an auto- 
matic tapper-back. One form of such tapper-back 
was then and there exhibited—a trembler or vibrator 
being mounted on the stand of a receiving filings- 
tube. This was afterwards improved, with Mr. E. E. 
Robinson’s help, into a rotating steel wheel dipping 
into oiled mercury. Our aim was to get signals on 
tape, with a siphon recorder, and not be satisfied 
with mere telephonic detection. We succeeded ; but 
more rapid progress would have been made had we 
stuck to the telephone, as wiser people did. 
TELEGRAPHY 1894 TO 1806. 
My Royal Institution (1894) lecture was heard by 
Dr. Muirhead, who immediately conceived the desire 
to apply it to practical telegraphy. When my lecture 
was published—as it was in the Electrician, with dia- 
grams roughly depicting the apparatus shown, drawn 
(some of them) skilfully but not always quite cor- 
rectly, by the then editor of the Electrician, Mr. W. H. 
Snell—it excited a good deal of interest ; stimulating, 
to the best of my belief, Capt. (now Admiral Sir Henry) 
Jackson, Prof. Righi, and Admiral Popoff to their 
various experimental successes which have been else- 
where described. 
I was too busy with teaching work to take up 
telegraphic or any other development ; nor had I the 
foresight to perceive, what has turned out to be, its 
extraordinary importance to the Navy, the Merchant 
Service, and indeed Land and War service too. But 
fortunately in Italy there was a man of sufficient 
insight to perceive much of this, and with leisure to 
devote himself to its practical development. In 1896 
Signor Marconi came to this country—and the rest is 
public knowledge. 
Man and the Ice Age. 
By Prof. W. J. 
A Pe great advance recently made in our knowledge 
of the Quaternary epoch begins with the observa- 
tions of General de Lamothe on the ancient shore-lines 
which run along the coast of Algeria at heights of about 
100, 60, 30, and 20 metres above the existing sea-level. 
They maintain their course with such remarkable 
uniformity that M. de Lamothe was unable to regard 
them as due to elevation of the land, and consequently 
attributed them to changes in the level of the sea, and 
was thus led to predict that similar shore-lines would 
be discovered on the opposite coast of the Mediterranean 
and particularly in Provence ; a prediction which was 
subsequently verified by Prof. Depéret. 
Next Prof. Gignoux, a friend and former pupil of 
Prof. Depéret, made a detailed investigation of these 
shore-lines and their associated deposits in the Western 
* A lecture delivered to the Geological Society of London on January ro. 
NO. 2784, VOL. 111] 
Sottas, F-.R.S. 
Mediterranean, and embodied his results in a masterly 
monograph. 
Finally, Prof. Depéret himself extended these in- 
vestigations to the Eastern Mediterranean and the 
west coast of the North Atlantic Ocean. In a com- 
prehensive review of the whole subject he proposed 
the following classification of the Quaternary deposits, 
based on the four marine terraces of de Lamothe. 
1. Srcit1an (Déderlein). Coast-line at from go to 
1oo m. The most perfect example of this stage is 
afforded by the Conca d’Oro or basin of Palermo, an 
ancient bay of the Mediterranean now filled up with 
Quaternary deposits. They commence with a blue 
clay containing near its base the famous fauna of 
Ficarazzo, which points to cold conditions and a depth 
of 90 metres. Traced towards those localities where 
the sea was clearer, the clay passes into a Polyzoonal 
ne ee. 
= 
