SCIENCE. 



3o5 



SCIENCE : 



A Weekly Record of Scientific 

 Progress. 



JOHN MICHELS, Editor. 



Published at 



TRIBUNE BUILDING, NEW YORK. 



P. O, BOX 3838. 



SATURDAY, JULY 2, 1881. 



THE NEW COMET. 



The great comet which has so suddenly flashed into 

 our Northern sky is one of the most brilliant comets 

 that has appeared for many years. It has a large and 

 very stellar like nucleus which is surrounded with en- 

 velopes, very much like those of the Donati comet of 

 1858, which was described so well by Protessor 

 George P. Bond of the Harvard College Observatory. 

 The dense nuclei of such comets give one the idea of 

 a mass and quantity of matter quite different from 

 the ordinary telescopic comets, through which the 

 faintest stars can be seen. The tail of the present 

 comet is now about twelve or fifteen degrees in 

 length, and altogether this comet presents a very 

 beautiful spectacle at three o'clock in the northeastern 

 morning sky. The motion of the comet is three or 

 four degrees toward the north, and it will soon reach 

 a position where it will be visible during the entire 

 night in the greater part of the United States. 



The first duty of the astronomers will be of course 

 to get observations of its positions and to compute 

 the orbit of the comet. Since for this purpose obser- 

 vations on three days are sufficient, we shall soon have 

 a certain knowledge of its motion. The knowledge 

 of the orbit will decide the question whether this is the 

 large comet whose discovery was telegraphed to 

 Europe from Buenos Ayres by Dr. B. A. Gould, on 

 June. 1st, and also whether it is identical with the 

 great comet of 1807. The observations of the comet 

 of 1807 were discussed in a very complete manner 

 by Bessel who found its periodic time to be between 

 1400 and 1900 years, and it will be a curious fact if 

 the true period proves to be only seventy four years. 



This great comet also presents a good opportunity 

 for the spectroscopists to examine its chemical nature, 

 and a rare occasion for the study of the physical con- 

 stitution of comets. No doubt these questions will 



be well attended to by the astronomers and students 

 of our country. 



The question of the formation of a comet's tail, and 

 how the particles of matter are driven out from the 

 nucleus in the direction opposite the sun has not yet 

 been answered in a satisfactory manner, and all the 

 facts that can be gathered from observations of this 

 comet will be extremely valuable. In his discussion 

 of the physical constitution of Hailey's comet in its 

 appearance of 1835 Bessel found that a repulsive 

 force from the sun was very decidedly shown by the 

 observations of the tail. Similar results were reached 

 by Professor Pierce of Harvard College, Professor 

 Norton of Yale College and by Dr. Pope in their dis- 

 cussion of the Donati comet of 1858. This is an in- 

 teresting question and it may have an intimate relation 

 with the theory of a resisting medium in space which 

 has been indicated by the motion of Encke's comet. 



We learn that unfortunately the weather at Wash- 

 ington has been unfavorable for several days past ; 

 but from the numerous good telescopes scattered over 

 the country, we doubt not that good observations of 

 this interesting comet will be gathered. 



THE ADDRESS OF THE PRESIDENT OF THE 

 ROYAL MICROSCOPICAL SOCIETY. 

 Lionel S. Beale, F. R. S. 



(Concluded from page 297.) 



One may transport oneself in imagination into infinite 

 space, amid the never-ceasing vibrations visible and in- 

 visible — "The lucid interspace of world and world, where 

 never creeps a cloud, or moves a wind," and may per- 

 haps all but see combined in one mental image, as they 

 ever course through space, suns and worlds and systems. 

 And although at first the mind is almost lost in the con- 

 templation of the infinite physical vastness presented it, 

 it is nevertheless able to seize in some degree a more 

 than shadowy conception of the exactness and regularity 

 of the eternal movements, and to recognize the never-ceas- 

 ing operation in the material universe of inflexible, un- 

 changing law. 



But he who in imagination can succeed in mentally 

 placing himself amid the atoms in the interatomic spaces 

 of a living particle, will be in the very heart as it were of 

 an infinity of a very different order — infinite movement 

 and change affecting infinitely minute particles, so very 

 near to one another that the matter of one may as it 

 were run into that of the other, and the masses divide 

 and subdivide again. Of all this movement and change 

 of particles how very little of what occurs in a ponion of 

 matter not more than the one hundred-thousandth of an 

 inch in diameter can be comprised in one mental image ? 

 But beyond all this there is the power of prospective 

 change, acting through years it may be, which is some- 

 how associated with the minute particles of living mat- 

 ter, as well as many complex phenomena of which the 

 mind cannot take cognizance as a whole, but must 

 consider, as it were, one by one in several successive 

 pictures. 



Could we peer into the very substance of the living 

 particle itself as it was increasing in size and commu- 

 nicating to non-living matter its wonderful properties, 

 what should we see? What is it that happens at the 

 moment when a little complex organic muter dissolved 



