92 



NATURE 



[Nov. 23, 18; 



a colloid membrane and water on the other, and Dr. Guthrie 

 thought it might be well to determine what action, if any, takes 

 place when a salt is added to a solution of a colloid such as size. 

 Two or three lumps of rock salt were added to a jelly of size, 

 and the whole hermetically sealed in a glass tube. The colloid 

 parted with its water readily, a saturated solution of the salt was 

 obtained, and the size became perfectly white and opaque, 

 having undergone a structural change. Experiments were also 

 made employing a more hygrometric salt, such as chloride of 

 calcium, — Mr. W. C. Roberts pomted out that a jelly containing 

 5 per cent, of silicic acid readily parts with water to sulphuric 

 acid, and dries into a hard glass like hydrate of silica. He asked 

 whether this might be considered as analogous to the action of 

 salt on size, or whether the strong affinity between the acid and 

 water removed it to another class of action. Dr. Guthrie thought 

 it might be possible to establish the existence of a point at which 

 the jelly did not give up its water to the hygrometric substance. 

 He also pointed out the analogy between a jelly s^nd a mass of 

 small bags filled with liquid. 



Entomological Society, November i. — Prof. Westwood, 

 president, in the chair. — Mr. F. Smith exhibited some remark- 

 able specimens of thorns from Natal and Brazil, which had been 

 taken possession of by certain species of Cryptoceridce for the 

 construction of their nests. Some of the thorns were as much as 

 3 inches in length. — Prof. Westwood mentioned an instance of 

 the hairs of a larva of Lasiocampa riibi having caused consider- 

 able irritation of the skin, and tha^ the irritation was complained 

 of by his correspondent for a week afterwards. — The Professor 

 exhibited a singular Coleopterous larva from Zanzibar, of a flat- 

 tened, ovate form and a steel-blue colour, with two points at the 

 extremity of the body, and with long, clavate antennce. The 

 head bore some resemblance to that of the dipterous genus 

 Diopsis. He also exhibited a specimen of the butterfly, Ihsperia 

 sylianus, received from the Rev. Mr. Higgins, of Liverpool, 

 having the pollinaria, apparently of an Orchid, attached to the 

 base of the tongue. Also an Orchid bulb purchased by Mr. 

 Hewitson with a collection of roots from Ecuador, which was 

 found to contain nine living specimens of cockroaches, compii.-ing 

 six different species, viz., Blatta orientalis, Americana, citterea, 

 Ataderce, and two others unknown to hini, some being of con- 

 siderable size. — Mr. Dunning read a " Note on Acentro/us," in 

 which he remarked on Hter Ritsema's Second Supplement to 

 his Histoiical Review of the genus, published in the Transactions 

 of the Entomological Society of the Netherlands, in which that 

 author tried to prove that two distinct species existed, of which 

 one [A, nivcus, Oliv. = A. Garnonsii, Curt.) has a female with 

 rudisnentary wmgs, and the other (^. latipennis, Moschl. — 

 Zancle Hansotii, Ste.), has a female with normally developed 

 wmgs ; whereas, Mr. Dunning argued that the facts, as stated 

 by Heer Ritsema, did not in any way prove the duality, but 

 were quite consistent with the unity of the species. 



Institution of Civil Engineers, November 14. — Mr. 

 George Robert Stephenson, president, in the chair. — The paper 

 read was on the Japan hghts, by Mr. R. H. Brunton. 



Paris 



Academy of Sciences, November 13. — Vice-Admiral Paris 

 in the chair. — The following papers were read : — Theorems rela- 

 tive to systems of three segments making a constant length, by 

 M. Chasles. — Note on the recent progress of phylloxera in the 

 departments of the two Charentes, by M. Bouilland. — Continua- 

 tion of observations of eclipses of Jupiter's satellites at the Obser- 

 vatory of Toulouse, by M. Tisserand . For eclipses of the first 

 satellite little seemed to be gained by using larger instruments ; 

 for those of the second and third the difference was greater. — M. 

 Milne-Edwards presented the first part of tome xii. of his work 

 on comparative physiology and anatomy of men and animals. It 

 treats of audidon and sight. — Report on a memoir of M . Fouque, 

 " Mineralogical and geological researches on the lavas and dykes 

 of Thera" (irland of Santorin group). These lavas contain two, 

 and often three triclinic felspars (some say volcanic rocks never 

 contain more than one) ; albite predominates among the small 

 crystals ; labradurite or anorthite among the large. These anor- 

 thite lavas (hitherto thought exceptional) form forty-one of the 

 dykes of Thera. M. Fouque shows, from experiments, that a 

 lava fused and suddenly cooled is quite as crystalline as when it 

 has solidified slowly ; crystals are formed before ejection from 

 the ground. Contrary to M. Tschermak, who would eliminate 

 from the catalogue of mineralogical species all triclinic felspars 

 except albite and anorthite, M. Fouque shows reason for retain- ; 



ing oligoclase and labradorite. Tridymite, a variety of crysl 

 listd silicon, is found in the lavas in form of thin hexago 

 imbricated plates ; M. Fouque regards it as a posterior format 

 to the other elements, and as having arisen at a high temperat 

 under the influence of imprisoned droplets of water, when 1 

 surrounding ro:k was liquid or viscous. The report speaks hig' 

 of the value of this memoir. — Researches on the brachistochro 

 of a heavy body, with regard to passive resistances, by M. Hal 

 de la Goupilliere. — On the characteristics of systems of con 

 and surfaces of the second order, by M. Halphen. — M. Frang 

 recommended, against phylloxera, the vitriolic water from I 

 mines of pyrites of Sainbel. — Observations rela'iveto the gene 

 theory of trombes, by M. Virlet d'Aoust. He describes so 

 dust whirlwinds observed on the Mexican plateaux.— Determii 

 tion, by the method of analytic correspondence, of the envelo] 

 surface of a surface whose equation contains n parametres ci 

 nected together only by « — 2 relations, by M. Saltel. — Influei 

 of temperature on magnetisation, by M. Gaugain. The value 

 the temporary variation varies considerably frjm one bar 

 another. To determine the influence of temperature this shoi 

 be kept invariable throughout an experiment ; the author ( 

 scribes how he accomplished this. With a bar susceplible 

 considerable temporary variation, the magnetism developed 

 300° is weaker than at ordinary temperature, but in the oppos 

 case it is stronger. — On the hydrates of sulphate of copper, 

 M. Magnier de la Source. — Onmargaric chloride and its derl' 

 fives, by M. Villiers. — Researches on quercite, by M. Pruni 

 He considers quercite to form a transition between the fa 

 series and the aromatic series. — On angelic acid, by M. Deny 

 9ay. He verifies his former experimental results against soi 

 contradiction of them by M. Fittig in the Berlin Chemi 

 Society. — Physiological experiments on the functions of t 

 nervous system of Echinida, by M. Fredericq. The coi 

 described as the nervous system are the means by whi 

 harmony of movements is established. Fa;ts seem also 

 favour the existence of a nervous plexus situated in t 

 thickness of the external tegument.— On the mobile sti 

 of Podophrya fixa, by M. Maupas. This, he says, har*. 

 merits its name ; it is more mobile and vagabond than kno' 

 Acinetinians, and is an intermediate type between suctorial in 

 soria and ciliated infusoria, properly sj called. He describes 

 detail the changes which take place in it during its mobile peric 

 —On the existence of asparagii'.e in sweet almonds, by i 

 Portes. — On the influence of leaves and floral branches oa t 

 nature and quantity of sugar contained in the scape of agave, 

 M. Balland. Both leaves and flowers have an incontestable r 

 in the formation of sugar. — On a meteoric iron very rich in nicl, 

 found in the province of Santa Catharina (Brazil), by MM. Guig 

 and Ozorio de Almeida ; iron 64 per cent., nickel 36. It a 

 pears to belong to the terrestrial rocks. M. Daubree remark 

 that a careful examination of all that region was very desiral. 

 —Chemical composition of the wa'.er of the Bay of Rio 

 Janeiro, by MM. Guignet and Teller. It contains consider,,' 

 quantities of silica and alumina (9 "5 and 7*5 gr. respectively, 

 cubic metre). This is from decomposition of the gndss a 

 granite rocks under friction of the water. 



CONTENTS Pa 



Ferrihk on the Braix, I. By George Henry Lewhs 



Greek and Latin Philology. By Rev. A. H. Sayce 



Our Book Shhlf : — 



Packard s " IWonograph of the Geometrid -Vfoths or Phaloenida: of 



the United States .... . 



Lbtteks to the Editor : — 



Prof. Balfour Stewart on Meteorological Research — Thomas Sth- 

 VENSON, C.E 



Ocoan Currents. —Capt. Digby Murray 



Dffiniteness and Accuracy. — Prof. P. G. Tait 



On the Internal FJuidity of the Earth. — Prof. Henry Hennessy 

 F.R.S 



The Age of the Rotks of Charnwood Forest. — Pro'. Edward Hli.i,, 

 F.R.S 



Mind and Matter. — Wm. S. Duncan . 



Meteor. — Cecil H. Sp. Percival 



The Present State of Mathematical Science. By^Prof. H. 



Smith, F.R.S 



The Austrian Akctic Expedition (M^i/A ///?«^?-rt//<?«.r) 



Our Insect Foes 



Carl Jelinek 



Our Astronomical Column : — 



The Distances of the Stars 



The Total solar Eclipses of 1239, June 3, and 1241, October 6 . . ' 

 Notes ' 



SCIKNTIFIC SeRI^iLS i . . ! 



Societies anb Academies • '. 



