July 13, 1893] 



NATURE 



25; 



The Essex Naturalist, No. 4, contains an address on 



periodicity in organic life, delivered by Mr. Henry Laver 



' as retiring President of the Essex Field Club. Reasons are 



given for the belief that plant and animal life periodically 



fluctuate in richness and scarcity. 



At Trenton, and the Delaware Valley, and Ohio, flints 

 i have been found in ice-age drift and described as implements 

 I of palaeolithic man. In three papers received from Mr. W. H. 

 ; Holmes this interpretation is disputed, and the "finds" are 

 ' said to be of Indian manufacture — a view which, if accepted, 

 \ tells against the existence of glacial man in America. 



' Profs. L. Ciccone and F. Campanile have prepared a 

 ; set of tables showing the intensity of gravity, in C.G.S. units, 

 1 for every ten minutes of latitude {Rivista Scientifico-Indtis- 

 triale). They also give the value of g at all the principal ob- 

 serving stations in the world. 



Owing to the delay in the publication, by the U. S. National 

 , Museum, of a " Monograph of the North American Bats," by 

 1 Dr. Harrison Allen, the introduction to the Bulletin has been 



issued in advance. Judging from it, the coming memoir will be 



of an important character. 



Messrs. Friedlander and Son, Berlin, have issued their 

 Natural History News, No. 10. 



The " Transactions of the Leicester Literary and Philoso- 

 phical Society," vol. ii., part 12, contains a paper on stings 

 j and poison fangs, by Mr. G. T, Mott, and a number of 

 notes on some East Anglian birds, by Mr. L. Creaghe- 

 Haward. 



A VOLUME has just been published containing the results of 

 rain, river, and evaporation observations made in New South 

 ' Wales during 1891, under the direction of Mr. H. C. Russell, 

 C.M.G., F. R.S , the Government Astronomer of the colony. 



In Djs Wetter for May G. Falkenhorst gives an account of 

 the various plants which are affected by weather, including the 

 paternoster pea (v^^z-ai /r^fa^w/'/w), or "weather plant," the 

 claims of which as a prognosticator of coming weather were 

 -hown to be groundless in the Kew Bulletin of January 1890. 

 He points out that the indications of these hygroscopic plants, 

 however worthy of study from a botanical point of view, only 

 refer to simultaneous changes of weather. 



The Royal University of Ireland has issued its calendar for 

 the year 1892. The papers set at the examination held during 

 the year are published in a separate volume as a supplement to 

 the calendar. 



The " Matriculation Directory " has been published by 

 the University Correspondence College Press. It contains 

 solutions to the questions set at the matriculation examination 

 ,of London University last month, and articles on the special 

 subjects for January and June next year. 



"Die Medicinische Electrotecknik," by Dr. J. L. 



Iloorweg, is a little book, dealing chiefly with elementary facts 



[and principles more or less connected with medical electricity. 



Magnetism, statical electricity, voltaic electricity, and electrical 



measurements are the subjects of four separate chapters, and 



the remaining three chapters are devoted to a study of the 



j action of electricity upon the human body, electro-medical 



[apparatus, and various methods of electrification. The text 



'is illustrated by seventy-seven figures and diagrams. 



I The second number of Alembic Club Reprints can now be 

 lobtained from Messrs. Simpkin, Marshall and Co. It is entitled 

 I "Foundations of the Atomic Theory," and contains reprints of 

 'papers by Dalton and VVollaston, and an extract from Dr. 



NO. 1237. VOL. 48] 



Thomas Thomson's " System of Chemistry," in which book 

 the earliest printed account of Dalton's views was given. 



A new acid containing chromium and sulphuric acid, possess, 

 ing somewhat remarkable properties, is described by M. Recoura 

 in thecurrent number of the Comptes Rendus. It is related topyro- 

 sulphuric acid, H2S2O7, in a manner somewhat similar to that 

 in which the chromosulphuric acid, (S04)„Cr2(SOjH).,, previously 

 prepared by M. Recoura, is related to ordinary sulphuric acid. 

 Its constitution is represented by the formula (SoO-H)4Cr2(OH)j. 

 Its most remarkable property is that the two atoms of hydroxylic 

 hydrogen are readily replaceable by metals to form salts, the 

 whole of which, even those yielded by the introduction of the 

 metals of the alkalies and of ammonium, are completely 

 insoluble in water, although the acid itself is readily soluble. It 

 has been termed chromopyrosulphuric acid. In order to 

 prepare it a solution containing one molecular equivalent of 

 chromic sulphate, Cr2(SO.i)3, and five molecular equivalents of 

 sulphuric acid is evaporated over a water-bath, when a syrupy 

 liquid of a deep green colour is eventually obtained. This 

 liquid is then further heated to a temperature of 110-115° f°'' 

 a couple of days, which treatment induces a complete change 

 of character and transparent tabular crystals of the new acid, 

 possessing a vitreous lustre and a bottle-green colour, are 

 deposited. Its formation is represented by the following 

 equation : — 



CrjCSOJa + 5H2S04 = (Sj07H)4Cr2(OH)2 + 2H2O. 



The properties of chromopyrosulphuric acid differ widely 

 from those of chromosulphuric acid. It is readily soluble in 

 water, forming an opaline yellowish-green solution. This solu- 

 tion yields precipitates with the solutions of all commonly 

 occurring salts, those of the alkalies not excepted. It may be 

 generally stated that upon the addition of the solution of anj 

 metallic salt whatever to a solution of chromopyrosulphuric 

 acid, a flocculent precipitate, more or less green in colour, is 

 obtained. The precipitate, however, is not chromopyrosulphuric 

 acid in which merely the hydroxylic hydrogen is replaced by 

 the metal of the salt employed. One half of the pyrosulphuric 

 acid is detached, and in contact with the water present produces 

 four molecules of free ordinary sulphuric acid. The salt preci- 

 cipitated is thus derived from the acid (S20-)oCr2(OH).2. For 

 instance, when a solution of potassium chloride is added to a 

 solution of chromopyrosulphuric acid the following change 

 occurs : — 



(S„0-H)4Cr2(OH)2 + 2KCI -f 2H2O = 



' ' (S20j.)2Cr2(OK)„ -h 2HCI -1- 4H2SO4. 



Similarly copper sulphate solution produces a pale green pre- 

 cipitate of the salt (Sa07)2Cr„<^^\cu. 



Solutions of caustic alkalies act like salts. Thus, when a solu- 

 tion of caustic soda of known strength is slowly added a pre- 

 cipitate of the sodium salt (3207)2Cr2(ONa)j is thrown down, and 

 the solution attains its neutral point when ten molecular 

 equivalents of soda have been addel, the amount required to 

 form the above salt and to neutralise the four molecules of 

 sulphuric acid liberated. M. Recoura has also isolated the acid 

 itself from which these salts are derived, and promises a de- 

 scription of its properties in a subsequent memoir. 



Notes from the Marine Biological Station, Plymouth. — Last 

 week's captures include the Nemertines Prosorhochmus 

 Clafaredii and Carinella linearis, numbers of the Polychcele 

 Myzostomum on Antedon rosacea, various species of the Pantopod 

 genera Pkoxichilus, Nymphon and Ammothea, the liopod 

 Apseudes talpa, the Schizopod Heteromysis formosa, the 

 Brachyuran Acheeus Cranchii, and the Nudibranchiate Mollusca 

 ALolidiella glauca and Galvina cingulala. The chains of the 



