June 7, 19 17] 



NATURE 



29. 



OUR ASTRONOMICAL COLUMN. 



Parallax of Barnard's "Runaway" Star. — In the 

 Journal of the British Astronomical Association for 

 April, it is stated that Prof. Schlesinger, of Allegheny, 

 has found a parallax of 052 ', and a proper motion in 

 R.A. of — 073' for the "runaway" star discovered 

 by Prof. Barnard (Nature, vol. xcviii., p, 196). Dr. 

 S. A. Mitchell's value for the parallax is 0-47'', and 

 that found at Yerkes Observatory by Dr. Lee is 0-55'. 

 The true value is evidently very close to half a second. 

 The star thus appears to come second to a Centauri 

 in point of distance, but is the nearest known star 

 which is visible in our latitudes. 



Distribution of Stars of Type O. — The important 

 investigations of Prof. Charlier on the distribution 

 and motions of stars of type B (Nature, vol. xcviii., 

 p. 116) have been extended to stars of type O by VV. 

 Gyllenberg {Arkiv for Matematik, vol. xi., No. 28). 

 The general principle of the method is that if the 

 temperature and radius be supposed constant for a 

 given class of stars, the distance of each individual 

 star is given by r = R.io'^ "-'", where m is the apparent 

 magnitude, and R is the distance corresponding to 

 apparent magnitude zero. In general, R is deter- 

 mined from the proper motions and radial velocities, 

 but alternative methods have been employed by Dr. 

 Gyllenberg for stars of type O (VVolf-Rayet stars). 

 The extension in space and the velocity distribution 

 show a close relation to the B stars, as would be 

 expected if the two classes are contiguous in the 

 spectral sequence. The absolute magnitude of the 

 O stars is —2-78, this being the magnitude at a distance 

 of I siriometer (=10* astronomical units). This result 

 is in close agreement with Charlier's value —2-45 to 



— 4-78 for the successive sub-classes of the B stars. 

 The O stars, however, show a much larger extension 

 than those of type B in the galactic plane. The 

 density of O stars in the neighbourhood of the sun is 

 0-0000x76 per cubic siriometer. 



A similar investigation for A stars has been made 

 by K. G. Malmquist. and for F stars by C. F. Lun- 

 dahl. 



The Minimum Radiation Visually Perceptible. — 

 The recent results of Ives with regard to the least 

 quantity of radiant energy capable of producing the 

 sensation of light (Nature, vol. xcviii., p. 216) have 

 been further investigated by Prof. H. N. Russell 

 (Astrophysiccd Journal, vol. xlv., p. 60). As before, 

 the metre-candle is taken to be of stellar magnitude 



— 14-18, while a source emitting light of wave-length 

 055 f^> and appearing like a star of the 6th mag- 

 nitude, is regarded as radiating energy at the rate of 

 1-35x10-* ergs per sec. per sq. cm. The modified fac- 

 tors are those referring to the diameter of the pupil 

 of the eye, and to the stellar magnitude of the faintest 

 visible object. Steavenson's .estimate of 85 mm. is 

 adopted for the former, and the limiting magnitude 

 is now taken to be 85, from observations made by 

 H. D. Curtis and the author. Since a "star of mag- 

 nitude 8-5 gives only one-tenth as much light as one 

 of the 6th magnitude, it follows that the amount. of 

 energy which would enter the eye from a light source 

 of maximum efficiency, and of magnitude 8-5, is 

 i;35x,io~*xo-57xo-io, or y-y x 10-^* ergs per sec. 

 This is regarded as the best available approximation 

 to the true rninimum visibile. According to this esti- 

 mate, the minimum perceptible radiation corresponds 

 to the reception by the eye of about 200 elementarv 

 quanta of radiation per second, or of one erg in 

 fortv vears. 



NO. 2484, VOL. 99] 



WHALEBONE WHALES OF NEW 

 ENGLAND.' 



\'\T1TH. a record of many previous American 

 *'' authors who had studied the whalebone 

 whales of the eastern shores of the United States, 

 it was no easy task for Mr. G. M. Allen to produce 

 anything novel in this monograph. Yet the systematic 

 manner in which he has handled the whole subject, 

 from synonymy to enemies and parasites, renders 

 the memoir hotti interesting and instructive, especially 

 in connection with the habits, appearances in life, dis- 

 position, food, breeding, commercial value, parasites, 

 and capture.^ Some general questions are also dealt 

 with, such as the notion of Ryder, the late able inves- 

 tigator of the fishes, that the tail-flukes of whales 

 probably represent degenerate hind feet, not the whole 

 limb, as Gray and some earlier authors held; whereas 

 Owen, Huxley, Flower, Parker, and Glaus were of 

 opinion that the whole hind limb was (externally) 

 suppressed or atrophied, and that flukes and dorsal fin 

 had been secondarily added. The author's country- 

 man. Gill, also thought that the flukes were derived 

 from the greatly hypertrophied integument of the 

 hind limbs, analogous to the hind limbs of the eared 

 seal, whilst the osseous elements have been atrophied, 

 basing this supposition on the fact that the dorsal and 

 ventral vessels are distinct, and that the crus, when 

 present, is in the line of the flukes. 



On th6 shores of New England (thaf is, from the 

 Bay of Fundy to Rhode Island, or thereabout) six well- 

 known forms occur, viz. the Atlantic riglit whale 

 (Eubalaena glacialis, Bonnaterre), the common ror- 

 qual (Balaenoptera physalus, L.), the "seL," pollack, or 

 Rudolphi's whale (B. borealis. Lesson), the great blue 

 whale, or Sibbald's rorqual (B. musculus, L.), the 

 little rorqual, or piked whale {B. acutoro strata, Lac^- 

 p^de), and, lastly, the humpback whale {Megaptera 

 nodosa, Bonnaterre). 



The author takes each species in succession, and 

 deals with it systematically, structurally, and under 

 the other heads already noted. Thus, under the Atlan- 

 tic right whale, which probably sweeps from pole to 

 pole, the vestigial femur, with its ligamentous rod 

 (tibia?), and the occasional double-headed first rib are 

 noted. It is lively when harpooned, rolling over and 

 over so as to wind the line round its body, and, it 

 may be, upsetting the boat and injuring its crew, or 

 in its active movements striking the boat with its 

 "bonnet" (a process at the tip of the snout). Its 

 numbers ha\d dimini^ed since the early settlers 

 peopled these shores (1620), though they were numer- 

 ous in 1700, when twenty-nine were killed in one day. 

 Now they are scarce. Its migrations northward and 

 southward, its food (chiefly Thysanoessa and Calanus), 

 and its breeding are described. In clearing up the 

 synonyms of the next species, the cosmopolitan com- 

 mon rorqual, the author has done good service; and 

 he appears to agree with Kiikenthal that it is the third 

 finger which is absent in the manus, and not the 

 thumb, since two branches of the median nerve go to 

 the space between the second and third digits. The 

 only trace of a hind limb is a papilla on each side of 

 the anus in the foetus. In addition to the movements 

 recorded, this finner, in a calm and glassy sea, when 

 reconnoitring, will quietly push its head nearly hori- 

 zontally out of the water and examine, for instance, 

 a boat with its occupants, and then slip underneath • 



1 "The Whalebone Whales of New Ensland." By G. M. Allen. 

 Memoirs of the Boston Society of Natural History-, vol. viii.. No. 2, 

 pp. io7-3-?», 16 plates and various fe.xt-figttre*. (Boston, September, 1916.) 



2 The American records of stranded as well as captured whales are credit 

 able so far as they go ; bnt the recently instituted system of notification by 

 the British Goiremment, acting through the staff of the British Museum, is 

 more trustworthy. 



