334 



KNOWLEDGE. 



September, 1913. 



But the electrical shocks must be very strong : weak 

 ones do not awake the insect. 



The strangest circumstance in the catalepsy of 

 Carausius is that this state arises from unknown 

 inner conditions. If the insect is in its active state 

 it is impossible to hypnotise it artificially, like a 

 cray-fish. One can lay the creature down, fix it 

 in a given position, stroke it gently, but nothing 

 happens : it makes responsive movements, but does 

 not become cataleptic. Only of its own accord and 

 without exterior excitement does Carausius become 

 so. Therefore, I have called this phenomenon 

 " autocatalepsy." 



From a biological standpoint the autocatalepsy is 

 nothing more than an accommodation to a highly 

 developed protective resemblance. A cataleptical 

 Carausius is not only motionless but remains in the 



same position in which the external factors — for 

 instance a breath of wind or a fallen twig or leaf — 

 have placed it. Its likeness to the inanimate 

 objects is increased and the insect is given an 

 extra chance of surviving in the struggle for 

 existence. 



My laboratory experiments have detected also 

 some interesting points in the physiology of the 

 catalepsy of Carausius (which I have described 

 elsewhere *), but biological observations on this 

 feature under natural conditions are wanting. 

 Perhaps some readers of " Knowledge " living in 

 tropical countries will give some attention to this 

 new question and make some observations on other 

 Phasmidae. It is possible that the catalepsy is a 

 feature of other representatives of this interesting 

 family. 



* Biologisches Centralblatt, 1913, April. 



CORRESPONDENCE. 



THE NUMBER OF DOUBLE STARS. 

 To the Editors of " Knowledge." 



Sirs, — Mr. Bellamy is correct in stating that the number 

 of double stars in Burnham's Catalogue is 13,665. I do not 

 know how the number I gave came to be printed. 



I hope you will let me remind him I found no fault with 

 Mr. Lewis's Catalogue. I did not depreciate his work. I 

 have no doubt Burnham would agree his work was incomplete, 

 but Mr. Lewis's is much more so in point of numbers, and 

 especially as it is only a reference catalogue for Struvian 

 stars, and, of course, does not include the very numerous 

 discoveries of Burnham, and is just as defective as regards 

 spectroscopic binaries as Burnham's. 



For the rest, Mr. Bellamy merely expresses his personal 

 preference for Lewis's, and leaves my criticisms entirely 

 untouched. EDWIN HOLMES. 



Hornsey Rise, N. 



Sirs, — By your courtesy I offer the following conclusions 

 upon Mr. Holmes' reply. 



1. Mr. Holmes' reply merely leaves the point unanswered — 

 that is, the "Standard Authority" (or Catalogue) — which I 

 take to be a work wherein the particular item required may 

 almost certainly be found. On page 293 I stated enough to 

 show that the Standard Catalogue of Double Stars (including 

 Spectroscopic Binaries) is still, and may long be, a 

 desideratum. 



2. I demur to Mr. Holmes' statement that he found no fault 

 with Mr. Lewis' Catalogue, for as the latter is a definite and 

 complete piece of work, it would be nearly impossible to do so ; 

 but he most distinctly does this, by depreciation, on page 239. 



3. The question of my personal opinion does not enter, as I 

 dealt with facts; so the matter may end and Mr. Holmes 

 may enjoy in print his original criticism on this point, which 

 was of an inaccurate, spiteful, and unnecessary character. I 

 have already proved the first ; the second and third were too 

 obvious. Personally, I may add that I have used Mr. 

 Burnham's Catalogue some hundreds of hours more than that 

 of Mr. Lewis, but not as a " Standard " Catalogue of Double 



F. A. 



Stars. 

 Oxford. 



BELLAMY. 



STELLAR DISTANCE UNITS. 



To the Editors of " Knowledge." 



Sirs, — A. J. H. seems to have overlooked the fact that 

 Kepler and Newton have each places assigned to them in 

 the Moon, and when we think of the millions of worlds waiting 



to be named or numbered, there is no reason to be afraid that 

 there will not be worlds to be christened, if necessary, after 

 the earth's great men and women. A new name for " Light 

 Year" was not asked for in June "Knowledge" as this is 

 easy to understand, and simple enough. In these days of 

 greater and more and more wonderful scientific researches 

 and discoveries, when men are trying to measure " White 

 Nebulae" and their distances, and so on, " Andromedes," 

 "Sirio Meters," " Star Ratios," " Units" have been mentioned 

 as measures of astronomical distances, so that there are now 

 several astronomical measures of length ; and when we try to 

 think of the unmeasurable, unknown, infinitude of space, with 

 all it contains, we may safely say, " More to follow." 



A short easy word is needed to represent the nearest 

 distance of the Earth from the Moon, and the second of arc 

 now being divided into tenths, hundredths and thousandths, 

 it is time some simple short words or signs were used for them. 



J. W. SCHOLES. 



Grimscar," j 



Huddersfield. 



SELBORNE EXTENSION LECTURES. 

 To the Editors of " Knowledge." 



Sirs, — It is one of the difficulties of the Secretaries of 

 local Scientific Societies and of Institutes to find, year after 

 year, new subjects for discussion and lecturers whom their 

 members have not previously heard. May I in this connection, 

 therefore, call the attention of your readers to a list of lectures 

 which I have compiled, and which is being printed in The 

 Selbome Magazine tor September. The various items have 

 in most cases been delivered before the Selborne Society, and, 

 in my capacity as Extension Lecture Secretary, I should be 

 very glad indeed to give any help that I could to local Scientific 

 Societies who are wanting good lectures of general interest, at 

 fees which they can afford to pay. I may add that in certain 

 cases the lecturers only wish to cover their expenses. The 

 subjects, as befits the Society which perpetuates the memory 

 of the author of "The Natural History and Antiquities of 

 Selborne," deal with plants and animals, with the forces of 

 Nature, and with Archaeology. Many of the lecturers have 

 series of slides illustrating other addresses than those of which 

 titles are given. 



In places where there are no local bodies the Selborne 



Society, under special circumstances, would arrange one or 



more lectures, which would come under the category of 



Selborne Local Lectures. 



,„ „ c PERCIVAL J. ASHTON. 



42, Bloomsbury Square, j 



London, W.C. 



