December 22, 1893.] 



SCIENCE. 



345 



Having the three sides of the spherical triangle t Ca, the 

 angle at C can be calculated, and it proves to be 

 53" 15' 26" for the 1st January, 1755. 



Owing to the Second Eotation the Pole P is carried 

 round C as a centre, at the annual rate of 40.9". Between 

 1755 and 1850 there are 95 j'ears, which multiiDlied by 

 40.9"^1° 4' 45 5" for the increase of the angle at C, which 

 becomes 54'" 20' 11.5" for 1850, when the Pole has reached 

 P'. 



-We then have P'C=29'= 25' 47" Ca=2G'^ 37' 3" and the 

 included angle P'Ca^54'-' 20' 11.5" to calculate P'a. 



By calculation P'a^24" 54' 21.2" and found by obser- 

 vation, 24'' 54' 21.4". 



For 1st Januarj', 1890, the angle C becomes 54"^ 47' 27.5" 

 and by calculation, as before, P'a^25'^ 5' 55", and by 

 the Nautical Almanac 1890, 1 January=25'^ 5' 54.8". 



Hence the polar distance can be calculated for 135 

 years to within one second; and, considering the uncer- 

 tainty of refraction, it is probable that the calculation is 

 more correct than observation. 



Such a result speaks for itself, and may well excite ad- 

 miration of General Drayson's perseverance during many 

 years of tedious calculation, until his labors have at last 

 been rewarded by the splendid discovery of the radius 

 of the circle described by the Pole of the Heavens, and 

 the centre of that circle. 



Had Newton with his marvellous intellect known, as we 

 do now, that an almost tropical climate existed in what 

 are now Arctic regions, and an Arctic one as low as 54'^ 

 of latitude; that the axis of the earth varied its inclina- 

 tion to the plane of the Ecliptic; and that vast elevations 

 and depressions had occurred upon the surface of the 

 Globe causing its centre of gravity to vary its position by 

 the consequences of these movements, as in transferring 

 enormous quantities of the waters of the sea from one 

 locality to another; who can doubt that he would have 

 discovered the manner in which the Pole of the Heavens 

 would have moved in obedience to the law of gyration? 

 And with such catalogues as we now possess, he might 

 have achieved the same results as have been obtained by 

 Drayson in discovering, as he has done, the details of the 

 .Second Rotation. At all events he would certainly have 

 attributed the Precession of the Equinoxes to the true 

 cause of this, and not to the assumed joint action of the 

 sun and moon on the protuberant Equatorial Zone. 



A SEGEEGATION OF FEESH-WATER FISHES. 



BY THEODOBE GILL, M. D., PH. D., WASHINGTON, D. C. 



One of the most remarkable facts in zoogeographj' is 

 the segregation of the greater part of fresh-water fishes 

 represented by the ostariophysal orders, that is, the 

 families Gharacinidae, Ci/prinidae, Siluridae and their sub- 

 divisions. These are all genetically related, and must 

 have developed from a common stock eaiij- accommodated 

 to the fresh water and subsequently differentiated into 

 many families and a host of genera with many hundreds 

 of species. The few marine representatives of that host 

 are the Ariinae, or Tachisurinae, and the Flolosidae, and 

 these must have diverged from primitive fresh-water 



types. 



Another case of segregation of a widely distinct series 

 of families has never been recognized, and attention 

 should be directed to it. It is that of the haj)lomous 

 fishes. 



The Haplomi are teleocephalous fishes with a pneumatic 

 duct and abdominal ventrals, and were considered by 

 Prof. Cope to be an order of physostomous fishes, in- 

 cluding Esocidae, Umbridae, Cyprinodonlidae and Hypsaeidae. 



These are evidently related to each other, although not 

 very closely, and are mostly fresh-water forms. There are 

 two other families which have hitherto found no satis- 

 factory resting place which I am disposed to associate 

 with the typical haplomes — Percopsidae and Ajjhre- 

 doderidae. 



If the six families thus associated are really genetically 

 related, we would have another series of families segre- 

 gated as a fresh-water grouiJ, and which must have been 

 long established. The only one of these six families with 

 marine representatives is Cypronodontidae, and this seems 

 to be the most generalized and most nearly related to the 

 Synentognathous fishes, on one hand, and the Perciform, 

 on the other. Whether the salt-water Cyprinodontids 

 are the descendents of primitive salt-water fishes or have 

 reverted to the sea in later times, is now an ojjen question. 

 This I do not propose to discuss at present, reserving it 

 for future consideration, as well as numerous collateral 

 questions which may suggest themselves. My only object 

 at jjresent is to draw attention to the zoOgeographical fact 

 mentioned and the morphological problem involved. 



It is noteworthy that all the families enumerated are 

 rejaresented in the United States, and half of them /■ 

 {li'ipaeidii', or Amhhjopsidae, Percopidae and Aphredoderidae) S ' 

 are found nowhere else. The JSsocidae and Umbridae are 

 represented in Europe as well as America. The Cyprino- 

 donlidae, or Poeciliidae, are generally distributed. All the 

 families are remarkably well defined. Finally, it may be 

 suggested that the unwonted position of the anus 

 (jugular or thoracic) of two {Amblyopsidae and Aphredoder- 

 idae) is possibly more than a mere coincidence, and may 

 be an inheritance from common ancestors. 



BIOLOGICAL INVESTIGATION IN BOTANY. 



BY J. CHRISTIAN BAY, BACTEEIOLOGIST OF THE IOWA STATE BOARD 

 OF HEALTH, AMES, IOWA. 



A COUPLE of smaller notes on the biological question, as 

 far as botany is concerned, were f)ublished by me in this 

 journal. To the first of these, What is biology ? this lit- 

 tle note is to be regarded as an apjaendix. Mj^ first paper 

 contained, originally, a number of notes on the modern 

 methods of biological investigation in botany; I kept 

 them back in order that they should not be misunder- 

 stood. 



A short time ago I received Professor N. Wille's inaug- 

 uration speech in taking the chair of botany at Chris- 

 tiania, Norway. Professor Wille has said, in a- few 

 words, what I wished to say on the occasion above re- 

 ferred to, Therefore, I shall quote him: 



"The so-called pilant-biology is a child of the Darwin- 

 ian theory of selection. It should be called, more cor- 

 rectly, oecology. This branch of investigation should em- 

 brace, as nearly as possible, the science of all life-phe- 

 nomena of plants, minus physiologj': in other words, 

 oecology is the science of the mutual relationshij) be- 

 tween the plant and the surrounding nature, when this 

 relationship does not rest upon physical and chemical 

 causes. 



"Oecology has still retained many reminiscences from 

 the teleological conception of earlier days, when nature as 

 a whole was thought of as created for the sake of being 

 jDrincipally of use to, or a plaything for, the human race. 

 Plant oecologists, or as they like to call thempelves, plant 

 biologists, have the idea that everything must be useful 

 or develojDed in a certain way in order to be of use for 

 certain purposes. 



'■We shall give an example of one of the typical repre- 

 sentatives of this line of study. He placed an ant on the 

 leaf of Sonchu.s, and found that the ant tore the cuticula, 

 so that the milk juice from the leaf came out. The resin 



