9° 



HARDWICKKS SCIENCE-GOSSIP. 



that in a cubic centimetre there was no fewer than 

 21,000 of them. 



Astronomers have always been much interested 

 in the "Great Red Spot" on the planet Jupiter. 

 Mr. Denning is of opinion that it represents an 

 opening in the aerial envelope of the planet through 

 which we see the denser vapours of its lower strata. 

 The lighter tints observed during the last few years 

 are probably due to the filling in of the cavity by the 

 encroachment of the clouds in the vicinity. Parts 

 of some of the more prominent belts display an 

 intense red hue, like that of the old red spot, and 

 they may be due to the same causes. 



The largest steamship ever constructed in Ireland 

 has just been completed by Messrs. Harland & 

 Wolf, for the Peninsular and Oriental Company. It 

 is called the " Oceana," and is 466 feet long, 6380 

 tons gross register, with engines working up to 7000 

 horse-power. She is said to be capable of attaining 

 the speed of sixteen knots an hour. The new vessel 

 left London with the mails on the 9th of March. 



It is not long since it was discovered that the basic 

 s'ag of our iron furnaces (hitherto a perfectly waste 

 material) contained so much valuable phosphates, that 

 when it was ground to a fine powder it made a splendid 

 artificial manure. The Staffordshire Steel Co. are 

 now grinding two hundred tons of it a week, and the 

 selling price runs up to forty-five shillings per ton. 



It is proposed to construct a bridge over the 

 Hudson, with a single span of 2850 feet, to be 

 145 feet above high water, and have a total length 

 of 6600 feet. The cables are to be carried on 

 towers 500 hundred feet high. 



Baron Richtofen, Professor of Geology in Berlin 

 University, and famous as one of the scientific 

 explorers of China, died on the 6'.h ult., in Silesia, at 

 the early age of 53. 



We have received a copy of "A Pocket List of 

 British Marine Mollusca," compiled by the Rev. 

 Geo. Bailey, F.R.M.S. It is excellently got up, and 

 convenient for the pocket. Price 6d., published by 

 Tindall & Co., High Street, Newmarket. 



We are pleased to notice that Mr. C. B. Plowright 

 is publishing " The British Uredinea; and Ustila- 

 ginere " (illustrated with woodcuts) in a vol. of 270 

 pages. Price, to subscribers, Js. 6d., to non-sub- 

 scribers, 10s. 6d. Forms of subscription to be had of 

 Messrs. Kegan Paul & Co. 



A remarkable paper was recently read before the 

 Liverpool Astronomical Society by the Rev. F. G. 

 Grensted, on "A Theory to account for the Airless 

 and Waterless condition of the Moon," to which are 

 appended some geological and physical notes, by 

 T. M. Reade, F.G.S. 



Professor I. B. Balfour (of Oxford University) 

 has been elected Professor of Botany in the Uni- 

 versity of Edinburgh, the chair formerly held by his 

 distinguished father. 



A new work on Astronomy by R. A. Proctor is 

 announced to appear in 2r. 6d. parts, the first part to 

 be published early in April. Publishers, Messrs. 

 Longman & Co. 



Some time ago we noticed the death t>f Mr. Thos. 

 Bolton, the widely-known purveyor of living micro- 

 scopic objects. We are glad to observe that his two 

 sons, Mr. T. E. Bolton and Mr. S. P. Bolton, are 

 carrying on their father's extensive business. 



Professor Herdman, of Liverpool, has just 

 published an interesting brochure, entitled " Puffin 

 Island Biological Station ; its Foundation and First 

 Season's Work." 



ZOOLOGY. 



Ballast-Bags of Seals. — At a recent meeting of 

 the British Naturalists' Society, Dr. A.J. Harrison, in 

 a paper on " The Ballast-bag of the Seal," said : 

 "According to the fishermen, the Otariae have an 

 internal pouch known as the ' ballast-bag ' because it 

 is always found to contain a number of rounded 

 stones. The presence of these is accounted for by 

 saying that when the animals grow very fat, they 

 become so buoyant as to be unable to sink below the 

 surface of the water without the aid of some ballast, 

 which they secure by swallowing stones." This theory 

 implies the possession by the seals of considerable 

 reasoning power. Observations have shown that the 

 so-called ballast-bag is only the stomach ; and ac- 

 cordingly some people have suggested that the stones 

 are intended to assist in the trituration of food in 

 somewhat the same manner as in the gizzard of fowls. 

 Other persons suppose the stones subserve no useful 

 purpose, and are accidentally introduced with the 

 food, or in play. In the seals and sea-lions at the 

 London Zoo similar rounded stones have been found, 

 large numbers of which are quite foreign to the 

 geographical character of the district. A Newfound- 

 land seal, which died at the Cliiton Zoo, in 1886, was 

 examined by Dr. Harrison, who found in the stomach, 

 gravel, nuts, and pieces of stick. 



Unrecorded Daphnias. — Having read in this 

 month's number of your paper an article on " Un- 

 recorded Daphnia " (p. 37), I beg to say that, in 

 connection with some new discoveries in Fish 

 Culture, made at Geneva, I have specimens of 

 Daphnia ("pulex," I am told) which might be of 

 interest to Mr. C. Rousselet, resembling, as they do, 

 the drawing he has sent you. I shall be happy to 

 supply a few specimens, should the matter be of 



