Jan. 22, 1880] 



NATURE 



275 



which shows that the ordinary dark line is simply due to absorp- 

 tion ? Put into the spectroscope, in place of the micrometer 

 wires, an opaque diaphragm of tinfoil with two narrow slits in it 

 at right angles to each other, thus X . Put the sodium flame 

 alone in front of the collimator slit, and by a little management 

 one of the bright lines can be brought to shine through the 

 vertical slit in the diaphragm, while it can also be seen as a sort 

 of star in the horizontal one below. Now bring the lime-light 

 behind the flame; the brightness of the vertical slit will at once 

 considerably increase, but the horizontal slit below exhibits what 

 was before the star, as an intensely dark spot in the midst of the 

 bright continuous streak of colour, showing very strikingly that 

 the apparent darkness of the line when no diaphragm is used, 

 is a mere effect of contrast. 



The paper referred to in the report as a discussion of "the 

 want of achromatism of the ordinary achromatic object-glass," 

 was a comparison of the secondary spectrum of a glass of the 

 usual form and of great excellence, formerly used by me at 

 Dartmouth College, with that of the instrument now used here. 

 The latter is of the Gauss form, and is found to be decidedly 

 superior in its colour corrections, while it is inferior in no other 

 respect. C. A. Young 



Princeton, N.Y., January 5 



Death of Captain Cook 



On reading a paper reprinted from the Memoirs of the Boston 

 Society of Natural History, vol. i. part 3, entitled "Notes on 

 the Volcanoes of the Hawaiian Islands," by William T. 

 Brigham, A.M., I find at page 370 the following strange 

 paragraph: "Starting from the western coast at Kealakeakiia 

 Bay — the memorable scene of Cook's punishment— the island 

 may be described," &c. 



With writers accustomed to the correct use of the English 

 language, the word punishment infers crime. Its use here by 

 Mr. Brigham may be only a bilious outpouring of New England 

 puritanism, but as it stands on the face of a grave scientific 

 paper, it is a permanent accusation against Capt. Cook, whose 

 reputatii n and memory as one of our greatest navigators and 

 geographical discoverers, deserve the reverence of every English- 

 man. If there be any charge against Capt. Cook's reputation or 

 moral character, which can justify the slur gratuitously cast upon 

 his character by Mr. Brigham, in the above passage, 1st it be 

 substantiated by one of his countrymen in your pages or else- 

 where, but if there be no grounds on which this grave slur is 

 justifiable, then let it not stand unchallenged by your permitting 

 this letter to appear in the pages of Nature. 



London, January 14 Robert Mallet 



Electricity of the Blowpipe "Flame" 



I have discovered what I believe to be an important fact, viz., 

 that the blue pyrocone produced by the blowpipe from an 

 ordinary gas-burner is not merely magnetic, but possesses 

 polarity, for its point attracts the nurth pole of a compass, and 

 reptls the south pole. W. A. Ross 



Acton House, Acton, W., January 17 



Suicide of Scorpion 



I MUST crave a bit of your space to beg Dr. Hutchinson 

 (vide Nature, vol. xxi. p. 226) to look to facts when he would 

 refute anything based upon facts, and not trust to inferences. 



My experience concerning scorpion suicide points to the fact 

 that the " central temperature" of a circle of glowing charcoal 

 embers (i.e. gloiving when first placed on the ground in the open 

 air, and left to die out gradually), one foot inner diameter, was 

 never greatly in excess of the summer heat, often above 40 

 C. in the shade in these parts, and no doubt greater at Peshaw ar. 

 I keep no record of this, but I have just made a circle of glowing 

 embers of the size of walnuts, one foot in diameter, on the 

 kitchen floor, before the open window, suspending immediately 

 a Casella standard in the centre and one inch from the ground, 

 and a highly graduated Secretan, two inches from charcoal and 

 one inch from the floor, both bulbs free, the result being : — 



Centre. — After three minutes, 49°"50 Cent. ; at fivemiautes it 

 had fallen to 46 , and continued to fall gradually. 



Two inches from charcoal. — The heat declined gradually from 

 76° C, to which it rose quickly in the beginning ; general tem- 

 perature of kitchen = 15 25 Cent. So much for Dr. Hutchin- 



son's glowing inference ! which points to little short of stupidity 

 on my part. 



The fad is that so far from being cruelly scorched, the scorpions 

 I have watched did not appear out of their element, except when 

 they tried to escape ; then they quickly receded before burning 

 themselves, and it was after many such attempts that they 

 " pierced their head with their sting and died," as I have stated. 



As to your correspondent's theory that "the heat kills die 

 scorpion," it does not follow from the experiments as I conducted 

 them ; and as for his defying any one to prove that the insect dies 

 in consequence of the self-inflicted sting, for my part I am no 

 entomologist, and consequently am unable to make the necessary 

 post-mortem examination. I simply stale what I saw several 

 times with a very good pair of eyes, though not, of course, 

 "patent double-million-magnifying gas microscopes of he.xlxa. 

 power." I now confirm the statement, and submit that if Dr. 

 Hutchinson's paternal solicitude for his scorpions (which feeling, 

 mind, I respect) prevents him making such cruel (?) tests, he 

 should be content to doubt, and not pit unsound inferences 

 against tangible evidence, much less hurl defiance at the heads ot 

 practical men. F. Gillman 



Prov. Jaen, Linares, Spain, January 12 



The Fertilisers of Alpine Flowers 

 A FEW years ago I stated my belief in this journal that lepidoptera 

 are far more frequent visitors and fertilisers of flowers, and 

 that from this cause by far more flowers are adapted to cro >S- 

 fertilisation by lepidoptera, in the Alps than in the lowland. 

 But it was then impossible for me to give a sufficient number of 

 facts. Now, therefore, having continued my observations in 

 the Alps during six summers, and being about to prepare a de- 

 tailed work on "Alpine Flowers, their Fertilisation by In-ects, 

 and their Adaptations to them," I will here give a statistical 

 statement of all visits of insects on flowers which I have 

 observed (1) in the lowland, (2) in the Alps generally, (3) 

 above the boundary of trees; the numbers under 1 being 

 extracted from my work, " Die Befruchtung der Blumen durch 

 Insekten, &c. " (Leipzig, 1S73). 



Tabular Statement of the Visits of Insects to Flowers, observed by 

 myself 



Hence of 1,000 different visits to flowers (differing either by 

 the species of flower or by the species of insect) those by — 



Lippstadt, January 10 



Hermann MUller 



"Ideal" Matter 



In Nature, vol. xxi. p. 185, you published a letter from 



Herr v. Nudeln, in which he alluded to the researches of Pro- 



