July 25. 1878 



NATURE 



^fj 



gas as in air. Grapes are capable of absorbing or losing 

 water when kept in a moist medium or in a dry medium. 

 As maturation advances, the acids diminish and the sugar 

 increases. The mechanism of maturation is stated to be 

 this : — Acids and glucose are formed in the plant, and 

 the sap conducts them to the grape ; the acids are con- 

 sumed in it, while the sugar is concentrated. When the 

 maturation is very advanced, the sugar is consumed in 

 its turn. 



Ripening of Grapes after Removal from the 

 Vine. — In the Gazetta chiniica Italiana, vii. 517, some 

 experiments by M. Pollacci are described, in which he 

 finds that the process of ripening continues for a certain 

 time after the grape has been removed from the parent 

 plant. The bunches of fruit removed were, as far as 

 possible, equally divided, and the quantity of glucose 

 and acid determined in the freshly-gathered grapes, as 

 also in portions kept in the shade for some ten or twelve 

 days. In all the portions which had been kept, the 

 glucose had increased, whilst the amount of acid had 

 diminished, showing that a certain amount of ripening 

 action had taken place ; this action, however, ceases after 

 a time, the ripening never attaining full maturity. 



Use of Methyl Chloride for the Production 

 of Low Temperatures. — At a recent meeting of the 

 French Physical Society, M. Vincent called attention to 

 the use of chloride of methyl for production of low tem- 

 peratures. It may be extracted in large quantities and 

 cheaply from the products of beet-root molasses. It is 

 normally gaseous, and liquefies under about four atmo- 

 spheres pressure, when it may be conveniently carried 

 about in iron or copper vessels, a store of cold at easy 

 disposal. On opening a cock the liquid will flow out and 

 give a bath at — 23°, its boiling temperature under atmo- 

 spheric pressure. If the vaporisation be intensified by a 

 current of air, the temperature descends to about — 55°. 

 M. Vincent has arranged an apparatus for utilisation of 

 such cold. He incloses two or three kilogrammes of 

 liquid chloride of methyl in a double wall enveloping a 

 bath of alcohol or chloride of calcium in solution, and 

 protected exteriorly by an isolating layer of cork raspings. 

 To obtain low temperatures, a cock is opened to allow 

 communication of the double envelope (through a 

 caoutchouc tube) with an air-pump. 



Formation of Hydrocarbons by the Action of 

 Water on Manganese Iron Alloys containing 

 Carbon. — Cloez found that by acting on Spiegeleisen with 

 dilute sulphuric acid bodies resembling the petroleum 

 hydrocarbons were formed. On trying the action of pure 

 water at 100° no results were obtained, while at 250° with 

 super-heated steam, a certain action was perceived which 

 increased with the temperature, being completed at a dark 

 red. The hydrocarbons, however, were again decom- 

 posed. The same author has since tested a series of 

 manganese alloys, and finds that the best results are 

 obtained by means of one containing roughly Mn 85, 

 Fe 6, C 3'5, Graphite 4, Si I'l. Small portions of this, 

 treated with boiling water, decomposed the latter with the 

 evolution of hydrogen, oily drops being simultaneously 

 formed, and the gas burning with a luminous flame showed 

 the presence of hydrocarbons. Another alloy of nearly 

 similar composition gave the following results : the flask 

 contained slightly alkaline water with a mixture of iron 

 and manganese oxides in suspension ; the liquid hydro- 

 carbons in the condenser were similar to those previously 

 found, the gases also burning with luminous flames. 

 He has thus shown that water alone at the proper tem- 

 perature decomposes manganese iron alloys containing 

 carbon. 



Action of Boron Fluoride on Certain Classes 

 of Organic Compounds.— This body has been found 

 by Fr. Landolph to combine in definite proportions, 

 equivalent for equivalent, with certain classes of organic 



bodies such as aldehydes, acetones, and also with 

 camphor. For his experiments the particular substances 

 examined were ethylic, valeric, and benzylic aldehydes, 

 ordinary acetone, euodic aldehyde (oil of rue), and 

 ordinary camphor. In all these cases considerable dis- 

 engagement of heat was manifested in the combinations 

 of the several substances. By the action of the fluoride 

 on acetone two products are obtained, the one boiling 

 between 130°- 140°, this being, according to the authorjthe 

 most definite ; another compound, however, exists which 

 boils at a temperature of 1 60°- 170°. The first is a fluid 

 of a syrupy consistence and yellow-green colour ; it burns 

 readily, giving a green flame, and is entirely decomposed 

 by water. The compound, with ethylic aldehyde, ethylen 

 fluoboride, C2H3BFI2, undergoes decomposition when 

 treated with water, into a body with a peculiar ethereal 

 odour, the composition of which, the author thinks, may 

 probably be CjHgFl. 



GEOGRAPHICAL NOTES 



In the just-published number of the Royal Geographi- 

 cal Society's Proceedings we find some useful remarks 

 by Mr. F. Galton, on what has recently been done and 

 what is further required for the advancement of geo- 

 graphical teaching. First and foremost, he says, is the 

 publication of that excellent book by Prof. Huxley, 

 " Physiography," which, starting from the simplest ele- 

 ments, led students steadily on to the higher conception 

 of physical geography and the most recent discoveries in 

 it. Next, Sir Walter Trevelyan, a former Secretary of 

 the Society, had felt so much the necessity of a better 

 form of text-book for geographical teaching that he 

 had placed a handsome sum at the disposal of the 

 Council to procure, if they were able to do so, the 

 compilation of a really good county geography, to 

 serve as an example for other similar works to be 

 used in elementary schools. Turning to what is required 

 in the future, Mr. Galton mentions that they have re- 

 ceived a letter from a master of one of the great public 

 schools, urging them to plan a system of diagrams ex- 

 planatory of different physical features. His own opinion, 

 Mr. Galton says, is that what is most urgently needed is 

 some simple and well-methodised system of experiments, 

 suited to illustrate lectures on the main features of 

 physical geography. He has no doubt that an extension 

 of the methods of illustrating the facts of physical geo- 

 graphy — as used by Prof. Tyndall and Dr. Carpenter — 

 on a small scale and on a lecture-room table, is perfectly 

 feasible. Thus, as every thunder-shower shows in the 

 streets the phenomena of erosion and deposition, he has 

 no doubt that, on a lecture-table, with a can to supply 

 water, and with a certain quantity of sand, gravel, and 

 clay, all the main phenomena of river-action, such as the 

 sifting of materials, the stratification of deposits, and the 

 formation of deltas, might be successfully shown. 



Means have recently been found, we learn from the 

 South Australian Register, for still further increasing the 

 usefulness of the Hon. (now Sir) T. Elder's camels on the 

 far northern stations with which he is connected. The 

 experiment of using them for draught purposes has been 

 tried, and recently two teams of six camels drew loads 

 of 5:^ tons each from Beltana to Port Augusta. The plan 

 adopted is to yoke the animals together something after 

 the manner in which bullocks are coupled, and one man 

 only is required to manage each team. It has been found 

 that the camels thrive well in the northern country ; the 

 number originally imported several years ago was about 

 100, of which the greater part died, as the land, by its corn- 

 parative richness, presented too great a contrast to their 

 native soil ; there are now, however, about 400 of their 

 descendants at Lake Hope, Umberatana, Beltana, and 

 other stations in the far north, and the race seems to be 

 thoroughly acclimatised. The camels have already been 



