ii6 



NATURE 



\yune 2, 1887 



silver of beautiful peach-blossom, rose, purple, and black colora- 

 tion ; (2) that these compounds (except under the influence 

 of light) possess great stability, and may be obtained by purely 

 chemical means in the entire absence of light ; (3) that the 

 red chloride shows a tendency to the reproduction of colours, 

 and may probably be the material of the thin films obtained by 

 Becquerel and others in their experiments on heliochromy ; (4) 

 that these substances constitute the actual material of the latent 

 or invisible photographic image, a material that may now be 

 obtained in any desired quantity without the aid of light. They 

 also form part of the visible product resulting from the action of 

 light on the silver haloids. This first contribution deals with 

 red silver chloride, and with the relations of photochloride to 

 heliochromy. The author considers that in the reactions here 

 described lies the future of heliochromy, and that this beautiful 

 red chloride may ultimately lead to the reproduction of natural 

 colours. — On the inter-relation of contemporaneous fossil floras 

 and faunas, by Charles A. White. A chief object of this paper 

 is to show that successive orders of fossil floras_ and faunas do 

 not necessarily correspond so absolutely with given geological 

 epochs as is generally assumed. On the contrary, the rate of 

 progress of biological evolution from epoch to epoch has neces- 

 sarily been variable, some contemporary species dying out at an 

 early date, while others live on into subsequent epochs, accord- 

 ing to the different conditions of their environments. Living 

 species of land mollusks, for instance, are found also associated 

 in the same strata with those of extinct genera and families of 

 Miocene vertebrates. It is also incidentally shown that no 

 European palseontological and geological classifications are 

 entirely applicable to the conditions prevailing in the American 

 continent.— The Eozoonal rock of Manhattan Island, by L. P. 

 Gratacap. An examination of the rock recently exposed in 

 New York when the cisterns were being constructed for the 

 Equitable Gaslight Company, leaves little room to doubt that 

 here a bed of hornblende has undergone a more or less complete 

 conversion into serpentine, the change being in some places 

 accelerated by the elimination of lime carbonate as calcite, and 

 probably elsewhere the double carbonate of lime and magnesia 

 as dolomite. — Terminal moraines in Maine, by George H. Stone. 

 The generally unequal distribution of the glacial drift in Maine 

 is well illustrated by the detailed description here given of its 

 chief terminal moraines. — Note on the enlargement of horn- 

 blendes and augites in fragmental and eruptive rocks, by C. R. 

 Van Hise. While recently studying the eruptive rocks of the 

 Penokee-Gogebic iron-bearing series in Michigan and Wisconsin, 

 the author met with cases of new growths occurring upon augite 

 and hornblende, corroborating the observations made by Fr. Becke 

 amongst the eruptive rocks of Lower Austria in 1883. In some 

 instances the augite has been completely, in others partly, changed 

 into hornblende, the rocks where these new growths occur being 

 altered diabases. — The great Acadian Paradoxides, by G. F. 

 Matthew. An almost complete specimen of this gigantic species 

 has recently been found in the Cambrian basin of St. John, 

 differing from any hitherto described, and mostly resembling the 

 P. bennettii of Newfoundland and P. harlani of Massachusetts. 

 — On the kin of Paradoxides {Olenelbis ?) kjerulfi, by G. F. 

 Matthew. The object of this paper is to throw some light on 

 the comparative age of the Paradoxides beds in Europe and 

 America, and the probable position of Olenellus in relation 

 thereto, the allies of P. kjertdji, Linrs., being chiefly considered. 

 — On Taconic beds and stratigraphy (continued), by James D. 

 Dana. This second communication, which is accompanied by 

 a large map of the Taconic region in Berkshire, Massachusetts, 

 deals specially with the middle and northern part of that region. 

 The author concludes generally that the limestone must be the 

 underlying rock for the lower and narrower portions of the 

 Taconic range, the schists of which are the same in kind, and 

 essentially continuous. Most of the limestones are referred to 

 the Lower Silurian age, some Cambrian also occurring. 



Rendiconti del R. Istituto Lombardo, March 31. — On some 

 methods of testing. the purity of drinking-waters, by Prof. L. 

 Maggi. Koch's method by cultivation in gelatine is shown to be 

 greatly inferior in efficacy to that of Fol and Dunant by cultiva- 

 tion in meat extract, the former detecting only 5700 bacterial 

 germs where the latter finds 100,000. The author points out 

 further that Fol and Dunant's is substantially the same as the 

 method already adopted at a much earlier date (1867) by him- 

 self and Prof. Giovanni Cantoni. — Meteorological observations 

 made at the Brera Observatory, Milan, for the month of 

 March. 



April 14. — Effects of a thunderbolt, by Prof. R. Ferrini 

 During a recent thunderstorm in Milan some planking place 

 over the mouth of a dry well and covered with cultivated eart 

 was removed by an electric discharge in such a way that th 

 earth was precipitated bodily into the well. A lightning-cor 

 ductor from a neighbouring building had its terminus in th 

 well, where it is suggested that the explosion took place with th 

 result described. — On the second derivatives of the potentiz 

 functions of space, by G. Morera. A simpler method than th? 

 of Holder {Beitrdge zur Poteutialtheorie) is here proposed fc 

 determining the existence of the second derivatives of th 

 potential function of a mass distributed in a space of thre 

 dimensions. — .The migrations of the tunny, by Prof. Pietr 

 Pavesi. The commonly-accepted view that the true tunn 

 {Orcynus thynnus, L.) is an oceanic fish migrating periodical! 

 from the Atlantic through the Strait of Gibraltar round th 

 Mediterranean basin is shown to be erroneous. This fish is, o 

 the contrary, essentially an inhabitant of the Mediterraneai 

 where it migrates between the shallows in the spawning-seaso 

 and the deep waters for the rest of the year, but rarely passin 

 in large numbers beyond the Strait of Gibraltar. 



Bulhtin de t Academic Roy ale de Belgique, March. — Memo 

 on bichlorureted alcohol, by Maurice Delacre. To ethyl 

 alcohol, CH3 — CH2(0H), correspond the three chlorurete 

 derivatives of alcoholic nature : (l) ClCHj — CH2(OH) 

 (2) CI2CH— CHaCOH) ; (3) CI3C— CH^COH). The first > 

 these having been determined by Wiirtz, and the third by Ga 

 zarolli-Thurnlack in 1881, the author has now succeeded i 

 obtaining the second, resulting from the action of zinc ethyl c 

 anhydrous bichlorureted aldehyde, CI2CH— CHO. His d 

 scription of the process adopted is accompanied by analytic 

 data and experimental determinations leaving no doubt as I 

 the nature of this compound. — On some derivatives of propan( 

 by C. Winssinger. ' During his protracted studies of th 

 substance the author has determined, contrary to the observ: 

 tions of Pierre and Puchot, the existence of a hydrate of propyl 

 alcohol boiling at 87° C. He has also prepared in a pure stai 

 the sulphuret of orthopropyl with boiling-point 142° instead ' 

 the hitherto accepted 130° to 135°. He further shows that 

 solution of the organic hydrosulphates in alcohol is continuous 

 decomposed during ebullition at contact with the alkaline hydr 

 sulphates, yielding organic sulphur with liberation of hydr 

 sulphuric acid. Lastly, he has determined some new compound 

 such as the oxysulphide of propyl, which is dissolved at 14° 

 to 15°, and combines with the nitrate of calcium ; a mon 

 orthopropylphosphoric acid, and a tri-orthopropylphosphor 

 ether. These substances are formed by the action of the penti 

 chloride of phosphorus or orthopropylic alcohol, and have tl 

 respective formulas, C3H7PO4H2 and (C3H7)3P04.— Research 

 on the localization and function of the alkaloids in plants, 1 

 MM. Errera, Ch. Maistriau, and G. Clautriau. For sever 

 years the authors have been engaged with the study of tl 

 alkaloids, especially in Colchicum aiitumnale, Nicotiana mact 

 phylla, Aconitum Napellus, and various species of Narcissi 

 They have so far arrived at the general conclusion that tl 

 alkaloids are formed chiefly in the more active tissues where tl 

 albuminoids are incessantly decomposed and transformed. Fro 

 these tissues the alkaloids gravitate towards the peripher 

 where they become more easily oxidized, and serve to prote 

 the plant against attack. Physiologically they are analogous 

 the alkaloids developed in some animals, such as snakes, to i 

 extraordinary degree'; and must be regarded as the waste 

 refuse of the protoplasmic activity afterwards turned to accou 

 for protective purposes. 



April. — Discovery of instruments of the Stone Age in t 

 Congo State, by Ed. Dupont. Some specimens of rude imp! 

 ments are described, which have recently been discovered 1 

 Capt. Zboinski on the left bank of the Lower Congo in tl 

 region of the cataracts below Stanley Pool. They occurred 

 a district covered with chips of quartzite in the neighbourhoi 

 of South Manyanga, where this rock crops out, indicating I 

 site of a former quarry or manufactory of such objects, such 

 have frequently been found in other parts of the world, but ve 

 seldom in Africa. They are unpolished, belonging to the False 

 lithic epoch, the presence of which along the west coast of Afn 

 has also been recently confirmed by similar finds, but in sik 

 in the Mossamedes district much further south. — On a case 

 chemical decomposition produced by pressure, by J. II. van 

 Hoff and W. Spring. Under a pressure of 6000 atmospheres 

 I a temperature of 40° C. the authors have succeeded in decoi 



