October 6, 1898] 



NATURE 



545 



If for X in the given series we substitute ir + e we have, 

 ■omitting the factor 2, 



- _y = sin e + i sin 2 e + i sin 3« + + - sin «« + . . . 



This series increases with n until ;/< = ir. Suppose, therefore, 



^ = k -, where >6 is a small fraction. The series will now be 



n 

 nearly equal to «« = kir, a finite quantity even if « = oo. 



Hence the value of y in the immediate vicinity of jt = ir is 

 not an isolated point y — o, but a straight line - y = nx. 



The same result is obtained by differentiation, which gives 



dy 



-f- = cos X — cos 2x + cos yx - . . . 



ax 



putting .1 ■ = IT + e this becomes 



_dy 



dx 



cos « + cos 2« + cos 3e + . . . + cos ne 



•which is nearly equal to n for values of we less than kit . 



It is difficult to see the meaning of the tangent if y were an 

 isolated point. Albert A. Michelson. 



The University of Chicago Ryerson Physical Laboratory, 

 September 6. 



Helium in the Atmosphere. 

 C. Friedlander and H. Kayser have independently claimed 

 to have found helium in the atmosphere. On examination of 

 some photographs of the spectrum of neon I have identified si.x 

 of the principal lines of helium, which thus establishes beyond 

 question the presence of this gas in the air. The amount 

 present in the neon it is, of course, impossible to estimate, but 

 the green line (wave-length 5016) is the brightest, as would be 

 expected from the low pressure of the helium in the neon. 



E. C. C. Baly. 

 University College, London, Gower Street, W.C, 

 September 28. 



The discovery of helium lines in the spe"ctrum of neon, by 

 Mr. E. C. C. Baly, will necessitate a modification of the views 

 we have expressed in our communication to the British 

 Association at Bristol. We there estimated the density of 

 neon at 9-6, allowing for the presence of a certain proportion 

 of argon unavoidably left in the neon. As it contains helium, 

 however, this is probably an under-estimate. It is unfor- 

 tunately not possible to form any estimate of the amount of 

 helium mixed with the neon from the relative intensity of 

 spectrum lines, as has been already shown by Dr. Collie and 

 one of us ; we do not despair, however, of removing a large 

 part, if not all of this helium, by taking advantage of the greater 

 solubility of neon than helium in liquid oxygen. 



The presence of helium, however, in no way alters our view 

 as to the position of neon in the periodic table. The number 

 9-6 implies an atomic weight of 192 ; and a somewhat higher 

 atomic weight would even better suit a position between fluorine, 

 19, and sodium, 23. William Ramsay. 



University College, London, Morris W. Travers. 



Gower-street, W.C, September 28. 



Chance or Vitalism.' 

 I AM glad to see that Prof. Karl Pearson has called attention 

 to Prof. Japp's address at Bristol. Only that one does not like 

 to criticise adversely a presidential address, I would at the time 

 have pointed out the weakness in the argument that Prof. 

 Pearson criticises. He does not go nearly so far in this criticism 

 as the circumstances warrant. It is conceded that right- and 

 left-handed crystals of quite sensible size are produced sufficiently 

 separated to be seen and handled as separate crystals. Now 

 assuming, what there is ever>' reason otherwise to think quite 

 probable, that life started from some few centres, the chances are, 

 not that it was equally divided between right- and left-handed 

 forms, but that one or other of these forms preponderated. In 

 fact, if life started from a single centre, it must have been either 

 right- or left-handed. Hence the fact adduced only shows, what 

 was otherwise very probable, that life started from a small 

 number of origins, possibly only one. 



Another reason for either a right- or left-handed structure in 

 living organisms on the earth, and one which diminishes the 

 force of the foregoing argument for a small number of origins, is 

 that it probably started either in the northern or in the southern 

 hemisphere, and in either case the rotation of the sun in the 

 heavens may be a sufficient cause for a right- or left-handed 

 structure in an organism growing under its influence. 



Geo. Fras. FitzGerald. 



Trinity College, Dublin, September 27. 



NO. 15 10, VOL. 58] 



In his presidential address to Section B of the British As- 

 sociation, Prof. Japp argues the necessity of supposing a 

 "directive force," or intelligence, to have guided the formation 

 of the first asymmetric substance. "Vitalism," which at one 

 time was supposed to regulate the physiology and even the 

 mechanics of organised beings, has passed more and more from 

 the foreground, till, in the vision of some it remains only as a 

 point in the vast distance of time at the origin of life. Is it to 

 disappear altogether ? 



A sensible quantity of a mixture of enantiomorphs contains 

 an enormous number of molecules. Chance determines the 

 relative proportion present of right- and left-handed forms. 

 Each molecule, having resulted from the action of symmetric 

 forces, has an even chance of being of one or the other. Hence, 

 the improbability of there being present a great preponderance 

 of one form over the other is so great, that it is inconceivable 

 that an optically active solution could result. To the above 

 contention of Prof. Japp, the reply is made by Prof. Karl 

 Pearson, in Nature of September 22, that a chance result, 

 however improbable, will occur, if sufficient opportunity be 

 allowed. He postulates the vast ages of the earth's history. 

 May we not, however, invoke chance to deal with masses in- 

 stead of molecules, and thus perhaps substitute weeks for ages ? 



Let us consider a solution, in which the numbers of right- and 

 left-handed molecules are very approximately equal, and which 

 is consequently optically inactive. In the slow evaporation of 

 the solvent, the right- and left-handed nuclei, about which the 

 substance crystallises, will viost probably be evenly distributed. 

 Their number will be extremely small in comparison with that 

 of the molecules, and, as chance determines their distribution, 

 it is not so highly improbable — it is at least conceivable — that 

 the crystals will be unevenly grouped. Suppose such to take 

 place and a partial re-solution, roughly in the lines of the dis- 

 tribution of the two varieties of crystals— a not very improbable 

 event— and we have an optically active solution. Chance has 

 here acted the part played by organised matter in the person 

 of M. Pasteur, by selecting and rejecting the oppositely formed 

 crystals. 



Is it yet possible to deny that the first ancestor of Icevo- 

 rotatory protein could have been built up from an asymmetric 

 substance, separated in some such way as the above, by the 

 play of chance upon the natural working of symmetric forces ? 

 Clement O. Bartru.m. 



17 Denning Road, Hampstead, N.W., September 24. 



The Moon's Course. 



May I refer Sir S. Wilks to the simple and beautifully 

 written autobiography of James Ferguson, F.R.S., self-taught 

 mechanician and astronomer ? I will quote a passage. 



" Soon afterwards " (the previous date was 1743) "it appeared 

 to me, that although the moon goes round the earth, and that 

 the sun is far on the outside of the moon's orbit — yet the moon's 

 motion must be in a line — that is, always concave toward the 

 sun : and upon making a delineation representing her absolute 

 path in the heavens— I found it to be really so. I then made a 

 simple machine for delineating both her path, and the earth's, on 

 a long paper laid on the floor. I carried the machine and the 

 delineation to the late Martin Folkes, Esquire, President of the 

 Royal Society, on a Thursday afternoon. He expressed great 

 satisfaction at seeing it, as it was a new discovery, and took me 

 that evening to the Royal Society, where I showed the de- 

 lineation and the method of doing it. When the business of 

 the Society was over, one of the members desired me to dine 

 with him the next Saturday at Hackney, telling me that his 

 name was Ellicott, and that he was a watchmaker. I accord- 

 ingly went and was kindly received by Mr. Ellicott, who then 

 showed me the very same kind of delineation and part of the 



