October 13, 1892] 



NA TURE 



575 



was the grave of a medicine man who had flourished more 

 than 200 years before, six successors having filled his office, 

 each one living to a good old age. Careful questioning failed 

 . evoke any other answer. When the coins were shown to 

 c Chilcats, they could not remember having ever seen such 

 objects. Lieut. BoUes concludes that the coins probably were 

 derived from a junk driven on the coast about two cen- 

 turies ago. "To those," he says, "who doubt the advent 

 of junks on the west coast at this early date, these facts will 

 probably not be satisfactory, but it will be necessary for 

 them to break down by direct evidence such a strong plea." 



Messrs. H. Alabaster, Gatehouse & Co. have now in 

 the press, shortly to be issued, a new work, entitled, " Domestic 

 Electric Lighting, treated from the Consumer's Standpoint." 

 The author is Mr. Ed. C. de Segundo. 



" The Electrician " Printing and Publishing Co., Limited, 

 have in preparation for their " Electrician" Series the following 



lumes : — "Electromagnetic Theory," by Oliver Heaviside ; 



Electrical Engineering Formulae, &c.", by W. Geipel and 

 II.Kilgour; "Submarine Cable Laying and Repairing," by 

 If. D. Wilkinson ; " Drum Armature Winding and Commuta- 

 tors : in Theory and Practice," by F. M. Weymouth; and 

 "Electricity as a Motive Power, "by Albion T. Snell, M.LC.E., 

 M.E. 



The first series of lectures given by the Sunday Lecture 

 S iciety begins on Sunday afternoon, October 23, in St. George's 

 Hall, Langham Place, at 4 p.m., when Dr. Andrew Wilson 

 will lecture on "The Distribution of Animals and what it 

 teaches." Lectures will subsequently be given by Mr. Willmott 

 Dixon; Prince Kropotkin ; Mr. R, Brundenell Carter; Mr. 

 Arthur W. Clayden ; Prof. H. Marshall Ward, F.R.S. ;and 

 Dr. E. E. Klein, F.R.S. 



Another memoir upon persulphuric acid and the persul- 

 phates is contributed by M. Berthelot to the Annales de Chimie 

 et de Physiqite. As described in our note of vol. xliv., p. 577, 

 the potassium, ammonium, and barium salts of this interesting 

 acid were obtained last year by Dr. Marshall, of Edinburgh, in 

 tolerably large quantity and in well-developed crystals. M. 

 Berthelot, to whom the honour of the first preparation of per- 

 sulphuric acid and its anhydride is due, now publishes his 

 further work upon the subject, fully confirming Dr. Marshall's 

 results, and adding a few more facts to our knowledge of the 

 acid and its salts. The form of electrolysis apparatus which has 

 been found by M. Berthelot to yield the best results consists of 

 a double cell, the inner vessel of which is constructed of porous 

 porcelain. The liquid contents of both the interior and exteriof 

 vessels are cooled by means of glass worms through which a 

 constant current of cold water is maintained. The inner cell of 

 150 c.c. capacity contains a concentrated solution of potassium 

 or ammonium sulphate, according as potassium or ammonium 

 persulphate is required, in sulphuric acid diluted with six or 

 seven times its volume of water. The nearer the composition 

 of this liquid approaches to that of a solution of bisulphate of 

 potassium or ammonium, the greater is the yield of persulphate. 

 The exterior cell is simply filled with dilute sulphuric acid. The 

 positive pole in the interior cell is most advantageously formed 

 by a stout platinum wire, about one millimetre in diameter, as 

 persulphuric acid is found by M. Berthelot to be rapidly decom- 

 posed in contact with a large surface of platinum. Platinum 

 sponge, indeed, instantly decomposes the acid or solutions of its 

 salts. The negative pole in the outer cell may conveniently take 

 the form of a large plate of platinum. The current employed 

 was one of three amperes derived from accumulators. At the 

 exjMration of fifteen to twenty hours the internal cell is found to 

 contain large quantities of beautiful crystals of the persulphate. 

 Tl.e usual yield of the potassium salt was 2025 grams, and of 

 NO. I I9S, VOL. 46] 



the more soluble ammonium salt as much as 40-45 grams, in 

 one operation. M. Berthelot has also obtained potassium per- 

 sulphate by the direct electrolysis of sulphuric acid and sub- 

 sequent addition to the product of a concentrated solution of 

 potassium bisulphate, crystals of potassium persulphate, KSO4, 

 being at once deposited. This mode of preparation is not so 

 advantageous as the method of production by the electrolysis 

 of potassium sulphate as above, but affords interesting proof 

 of the formation of free persulphuric acid by the electrolysis of 

 oil of vitriol. M. Berthelot has further succeeded in prepaiing 

 persulphuric acid by the gradual addition of anhydrous barium 

 peroxide to concentrated sulphuric acid in a small flask sur- 

 rounded by ice. So rapid is the action that if the addition of 

 the peroxide is continued until the sulphuric acid is almost 

 exhausted, even although the vessel is maintained in pounded 

 ice, dense vapours are evolved which possess the remarkable 

 odour and other properties of persulphuric anhydride. Another 

 interesting fact observed by M. Berthelot is that a solution 

 of potassium persulphate attacks mercury, even at the ordinary 

 temperature, with production of a yellow basic sulphate which 

 appears to be identical with the salt known since the times of 

 the alchemists as turpith mineral. 



The additions to the Zoological Society's Gardens during the 

 past week include a Macaque Monkey {Macacus cynomolgus) 

 from India, presented by Miss E. A. Hill ; two Racoons {Pro- 

 cyon lotor) from North America, presented by Captain Sharp ; 

 a grey Idineumon {Hi rpestes s^risetts) from India, presented by 

 Mrs. Wyndham Bewes ; a Stanleyan Chevrotain ( Tragulus 

 stanleyanus) from Java, presented by Mr. Chas. J. Noble ; a 

 Vulpine Phalanger {Phalaugista vulpina, S ) from Australia, 

 presented by Master H. H. Barret ; a White Stork {Ciconia 

 alba), European, presented by Sir H. Rae-Reid, Bart., F.Z.S. ; 

 an Ostrich {Struthio camelus, 6) from Africa, presented by 

 H.M. the Queen ; a Common Chameleon (Chamceleon vulgaris) 

 from North Africa, presented by Mrs. Davidson ; three Negro 

 Tamarins {Midas nrsulus) from Guiana ; a Canarian Laurel 

 Pigeon {Columba laurivora, $) from the island of Gomera, 

 Canary Islands ; two Nicobar Pigeons {Colcenas nicobarica) from 

 the Indian Archipelago, deposited ; an Indian Muntjac {Cervu- 

 Itis muntjac, ? ) from India ; four Ringed Plovers (yEgialitis 

 hiaticula) and two Dunlins ( Tringa alpina), British, purchased. 



OUR ASTRONOMICAL COLUMN. 

 Luminous Night Clouds. — In an article communicated to 

 Astronomische Nachrichten, No. 3 1 20, Herren W. Foerster 

 and O. Jesse invite astronomers and geophysicists both 

 here and abroad to make observations of the very interest- 

 ing phenomena of luminous night clouds, the appearance 

 of which has, up till now, been observed more or less only 

 at Berlin. Since the year 1885, the authors tell us, these 

 appearances have been most noticeable, and it is because they 

 are now becoming less so that they wish to have as many ob- 

 servations made as possible. The phenomenon appears in the 

 form of cirrus clouds, which stand out bright against the twilight 

 sky. The colour generally noticed is that of a bluish white, and 

 when the horizon is approached, gold and red tints are added. 

 The best time for observation is said to be just before and after 

 sunrise and sunset. From photographs taken at Berlin, it has 

 been computed that these clouds are at a height of 82 kilo- 

 metres. Long after the sun has set they are seen to reflect the 

 sunlight, but as soon as they fall within the reach of the earth's 

 shadow they immediately become invisible. The observations 

 show, so far as may be judged from those already at hand, that 

 the movements of this phenomenon after midnight are directed 

 from the north-east ± 40°, and the authors think it highly 

 probable that the resistance of the medium surrounding the 

 earth accounts for these movements. This is to a certain extent 

 affirmed by observations made at Punta Arenas and other places, 

 the phenomena occurring six months after the conclusion of the 

 Berlin observations. Tlie authors suggest that eye observations 



