WCP2826

[1]¹

ROYAL ASTRONOMICAL SOCIETY OF CANADA

Toronto Canada

May 22 [19]03²

Dr Alfred Russel Wallace

Dear Sir:

I have read with pleasure your article on "Man’s Place in the Universe"³ also the criticism of the same by Prof[essor] W. H. Pickering⁴ Prof[essor] W. A. Maunder⁵ [sic], Prof[essor] Turner⁶ and Flammarion⁷. Though not a professional astronomer I have endeavored [sic] to make myself familiar with ^{the development} of astronomical theory and the recent advances that have been made along the ^{lines of} physical application and I must say with all due respect to the critics referred to[,] they have failed to show that the major portion of the astronomical facts you cite are in error or that your application of them, in your general argument, is seriously at falt [sic]. Though they have succeeded in pointing out one or two minor errors — (such as proportional to the distance instead of the square of the distance) each of the critic’s [sic] articles have contained errors [sic] ^{serious errors} which as professional astronomers they should ^not have made. Pickering treats the argument more fairly than any of the others and still, in opposition to statement that dark patches such as the "coal sacks" in the Southern portion of the "Milky Way" ^{are actual holes therein he says they may} may [sic] really be dark nebula [sic] between us and the Milk[y] Way. When the records of his own observatory will show that these regions to show multitudes of stars on the photographic plate and the analysis of this spectrum shows these stars to be of the same physical structure as the characteristic stars of the Milky Way in the immediate vicinity [2]⁸ also that they fail to show any extra absorption effects that should show if the light emenating [sic] from them passed through a dark nebula[.] Professor Turner seems to be positive that the nebula photographed around "Nova Persei"⁹ is a formerly dark nebula illuminat illuminated by light from the nova. Now I have before me a letter from Prof[essor] Perrine¹⁰ of the Lick Observatory¹¹ dated May the 10^th 1903 in which he expresses doubt of the correctness of this view and while he thinks the question an open one he is inclined to think that the nebula is or was self luminous for several reasons. 1^st points of condensation (shown on plates I inclose [sic] you) preserve their formation through moving outwards and longitudinally for great distances — note the amount of these displacements on the plotted plates each square of which represents 2’ of arc (though these plates were taken by Ritchey¹² of Yerke’s¹³ the[y] are the same in effect as Perrine[’]s taken at the Lick)[.] 2^nd the light from the nebula failed to show polarization — which it should have shown if reflected at the observed angle. The greatest difficulty he remarks in the way of supposing the light to terminate directly is not the great radial velocity of expansion of [the] nebula but to these account for the great apparent tangential motion — In this instance Prof[essor] Turner shows, to say the least a lack of caution to drag in a doubtful assumption and make it do duty as a certified fact and a fact too illustrating the rapid progress of "astronomical science". Mr Maunder however endeavors [sic] to be the most severe of all as regards ratio of aperture to number of stars[;] he thinks that absorption of the glass "to account in part at least" for the disappearance of the extra stars — failing to note that the reflector was used when determining this point, as well as the refractor[,] and further that Gill¹⁴ used a large telescope at the Cape¹⁵ when determining this and cut the aperture gradually down but did not thin or thicken the glass. He fails also to observe that the absorption of the ether, cosmic dust, and dark bodies in space were considered by Sir John Herschel¹⁶ who thought these considerations insufficient in his "Outlines of Astronomy"¹⁷ years ago and further, physisist [sic] though they have sought for it diligently have failed to find any evidence that the "ether" is capable of absorbing heat or light or any other form of energy[,] and even if [3]¹⁸ it did absorb[,] an increase of aperture should increase the light grasp[,] otherwise if the universe of ether should if absorbing for an infinite time be now infinitely hot. Mr Maunder’s suggestion that the dark bodies of space are of a "higher order" of impurity than the bright ones, must surely have been put forward as a joke, one would hardly suppose that a number could be found greater than an infinite. Then again the motion of the sun in space coming from the other side of nowhere may be put down to another joke as the exact[?] position of the apex of the sun[’]s way has been shifted, to such an extent as to leave it an open question whether its path is a straight line or a curve[.] Then as to the ability of other planets Galileo¹⁹ and the early observational astronomers found it absolutely necessary to explain to everybody that the stars and planets were probably all inhabited [.] The spectroscope as you have observed put the stars themselves beyond the pale and as Pickering remarks there are less than 1% of other stars of the solar type[,] the possible number of planets suitable for life decrease as well — and you go a step further and give reasons for supposing that perhaps the earth alone may be the only inhabited celestial body.

Mr Maunder thinks that the ether[,] if it had a boundary would dissipate into the space beyond — no doubt it would if constituted as a gas, having molecules rebounding against each other but physisists [sic] now insist (namely Kelvin²⁰ for instance) that the ether is a continuous inseparable thing, and if such a medium had boundaries these boundaries would be extremely elastic[,] and any specialized forms of the media rushing [4]²¹ against the interior surface would be thrown back with the force with which it came — so that it would not need to have come from beyond nowhere nor to go beyond nowhere to keep up its motion even in a straight line[.]

I think sir that you deserve a great deal of thanks for directing attention to points that have been ignored to a great extent by those who are supposed to be specialists in this particular department[.]

Yours very truly | J. R. Collins²² [signature]

(Secretary Royal Ast[ronomical] Soc[iety] of Canada)²³