140 A Field Naturalists Holiday. [Sess. 
was a rosy feather-star on its stem, like an encrinite, called 
after the “Hirondelle”; and there was a cuttle-fish with scales. 
We might have gone to many other places to interest a field 
naturalist. The aquarium was not much for us who live beside 
the sea, but in it there were some pillars of the Temple of 
Serapis from near Naples. Now, although I had seen the 
temple several times before at Pozzuoli, I don’t think I ever 
touched a pillar of it: here I put my finger into the holes the 
boring shells had made when it was under the sea. The 
Temple of Serapis is one of the few records we have of a great 
change of sea-level—a great sinking and a considerable rising 
again—within historic times. 
Before leaving the Exhibition for good I must go to have one 
more look at what I think is the most wonderful instrument I 
have ever seen. It is the telephonograph, invented by a Dane, 
Poulsen. It consists of a cylinder very much like that of an 
ordinary phonograph, but instead of being made of wax it has 
wire coiled round it of steel or nickel. A small electro-magnet 
the size of half an inch of an ordinary pencil comes down upon 
the coil, so that the wire passes between the poles. Now, 
the extraordinary thing is that the molecular condition of the 
wire is changed : it preserves a record of what has been spoken, 
and by beginning again and listening instead of speaking, the 
steel wire will repeat all that has been spoken. The wire 
retains the words, it is said, for some years at least. The whole 
may be obliterated instantly by an electric current passed 
through the wire. Have we not here an extraordinary de- 
monstration of the wonderful structure of matter ?—shall we 
call it the memory of matter ? 
17th Oct. 1901.—In his evening discourse on “ Movement 
of Plants” at the meeting of the British Association at Glas- 
gow last month, Prof. Francis Darwin expressed his opinion 
that plant movement might be regarded as psychological, in- 
volving some kind of memory or consciousness. He referred 
particularly to Prof. Hering’s lecture, “On Memory as a Uni- 
versal Function of Organised Matter,” delivered before the 
Vienna Academy of Sciences, 1870, and also to Samuel 
Butler’s “ Life and Habit,” 1878, and “ Unconscious Memory,” 
1880, as supporting this view. Possibly, in the controversy 
