ADDRESS. cm 



I shall read from Herschd's Astronomy, and from the fact that even SchiapareUi 

 seems still to believe in the repulsion. " There is, beyond question, some 

 " pi-ofound secret and mystery of nature concerned in the phenomenon of 

 " their tails. Perhaps it is not too much to hope that future observation, 

 " borrowing every aid from rational speculation, grounded on the progress of 

 " physical science generally (especially those branches of it which relate to 

 " the ethereal or imponderable elements), may enable us ere long to penetrate 

 '' this mystery, and to declare whether it is really matter in the ordinary 

 " acceptation of the term which is projected from their heads with such 

 " extraordinaiy velocity, and if not impelUcl, at least directed, in its course, 

 " by reference to the Sun, as its point of avoidance " *. 



" In no respect is the question as to the materiality of the tail more for- 

 " cibly pressed on us for consideration than in that of the enormous sweep 

 " which it makes round the sun in perihelio in the manner of a straight and 

 " rigid rod, in defiance of the laiu of gravitation, nay, even, of the receivedlaws 

 "of motion"*. 



" The projection of this ray . . . to so enormous a length, in a single day, 

 " conveys an impression of the intensity of the forces acting to produce such 

 '•■ a velocity of material transfer through space, such as no other natural phe- 

 " nomenon is capable of exciting. It is clear that if weJiave to deal here with 

 " matter, such as we conceive it (viz. possessing inertia^, at all, it must be under 

 " the dominion of forces incomparably more energetic than gravitation, and 

 " quite of a different nature " t. 



Think, now, of the admirable simplicity with which Tait's beautiful " sea- 

 bird analogy," as it has been caUed, can explain all these phenomena. 



The essence of science, as is weU illustrated by astronomy and 

 cosmical physics, consists in inferring antecedent conditions, and an- 

 ticipating future evolutions, from phenomena which have actually come 

 under observation. In biology the difficulties of successfully acting up 

 to this ideal are prodigious. The earnest naturalists of the present day 

 are, however, not appalled or paralyzed by them, and are struggling boldly 

 and laboriously to pass out of the mere " ISTatural History stage " of 

 their study, and bring zoology within the range of Xatural Philosophy. 

 A very ancient speculation, stiU clung to by many naturalists (so much so 

 that I have a choice of modern terms to quote in expressing it), supposes that, 

 under meteorological conditions very different from the present, dead matter 

 may have run together or crystallized or fermented into "germs of life," 

 or " organic cells," or " protoplasm." But science brings a vast mass of in- 

 ductive evidence against this hypothesis of spontaneous generation, as you 

 have heard from my predecessor in the Presidential chair. Careful enough 

 scrutiny has, in every case up to the present day, discovered life as antecedent 

 to life. Dead matter cannot become living without coming under the influ- 

 ence of matter previously alive. This seems to me as sure a teaching of science 

 as the law of gravitation. I utterly repudiate, as opposed to all philosophical 

 uniformitarianism, the assumption of " different meteorological conditions " — 

 that is to say, somewhat different vicissitudes of temperature, pressure, 



referred to appeared, to show that the other four orbits offered by Newton were inadmissible. 

 But the calculations to be gone through to find the secular motion of the node in such an 

 elongated orbit as that of the meteors were necessarily very long, so that they were not 

 completed till about March 1867. They were communicated in that mouth to the 

 Cambridge Philosophical Society, and in the month following to the Astronomical 

 Society. 



* Herschel's Astronomy, § 599. 



t Herschel's Astronomy, 10th edition, § 589. 



7i2 



