136 



NATURE 



[pec. 16, 1875 



purposes. Four persons were injured and the others experienced 

 severe bruises. The real cause of the catastrophe is to be inves- 

 tigated officially by M. GifTard, the celebrated French engineer. 

 At present it is supposed that the band of india-rubber which 

 acts as a spring gave way under influence of the frosty weather. 



The Italian Geographical Society (the Z>a?/yiVrtw Roman corre- 

 spondent telegraphs) held its first monthly meeting of the winter 

 session on Sunday. Capt. Barrattieri read the report of the Society's 

 expedition to the Tunisian Sahara last June. It gave interesting 

 details of the journey to Gabes, to the Island of Gerba, and to 

 other islands, described the country minutely, and proved the 

 impossibility of the French project for connecting the Sahara 

 with the Mediterranean by canal. The next paper, that of 

 Deputy Caperio, on the latest explorations of Lake Victoria, 

 dwelt on the importance of investigating the sources of the Nile 

 between the mountains parallel to the coast and Lake Victoria. 

 This was the task of the Italian expedition. 



In illustration of some remarks in the address of the presi- 

 dent, Mr. H. R. Robson, of the Scottish Institution of Engineers 

 and Shipbuilders, the number of the Transactions of that Society 

 just published contains a large and carefully executed plate 

 exhibiting a section of the Sub-Wcalden bore-hole to the depth 

 of 940 feet. 



No. 166 of the Notisblatt des Vereins fur Erdkunde %u Darmstadt 

 und dts Mittehheinischen geologischen Vereins contains a detailed 

 ristimi of the meteorological observations made at Darmstadt 

 during 1874, accompanied with a neat and cleanly constructed 

 diagram showing the daily and monthly results ; and also the max'- 

 mum and minimum temperatures, rainfall, and fog at six stations, 

 during September 1875, in the Grand Duchy of Hesse. Among 

 the many points detailed in the summary for Darmstadt may be 

 noted the dates of the last and the first snow in the course of the 

 year, the last and first frost, the last and first frost-day, mean 

 temperature being 32° or lower ; the number of frost-days each 

 month, and of summer-days, temperature being 77° 'O, or higher, 

 and the particular days on which thunder and other weather- 

 phenomena occurred. From November to June the ozone was 

 greatly in excess during the night, but during the other months 

 the excess occurred during the day. Among other matters, there 

 is an interesting table of the mortality durhig September last 

 from various disease?, at thirteen towns in the Grand Duchy. 

 The deaths from diarrhcea alone, which amounted to sixty- 

 two, were a sixth of the whole. This high diarrhoea death- 

 rate, which is three times greater than that of London during 

 the same season, and the unequal manner in which these deaths, 

 as well as deaths from phthisis, convulsions, and brain diseases, 

 are distributed among the thirteen towns, suggest the desirable- 

 ness of an inquiry into their sanitary conditions. 



At recent meetings of the Executive Committee of the British 

 Pharmaceutical Conference, grants amounting in all to 75/., were 

 made to a number of chemists for the purpose of obtaining ma- 

 terial to enable them to carry on scientific researches into the 

 nature and properties of certain substances used in pharmacy. 



The additions to the Zoological Society's Gardens daring the 

 past week include a Yellow-fronted Amazon {Chrysotis ochro- 

 cepkala) from Demerara, presented by Mrs. Sproston ; a Tree 

 Sparrow [Passer montanus), two Mountain Linnets {Linaria 

 fiavirostris), European, purchased ; a West African Python 

 (Python sebce) from West Africa, presented by Mr. W. H. 

 Berkeley. 



At the annual meeting on the 4th inst. of the Huddersfield 

 Naturalists' Society, the Secretary read a satisfactory report. 

 The number of members is 134, the finances are in a flourishing 

 condition, and during the past year twenty-two papers have been 

 read. . . 



ON SOME PROPERTIES OF GALLIUM 



TN a communication just made to the French Academy, M. 

 -*■ Lecoq de Boisbaudran states that he has succeeded, after 

 considerable labour, in obtaining salts of gallium sufficiently 

 pure to give, in addition to the gallium spectrum, only faint 

 traces of the zinc lines Zn o 144 '62 and Zn 7 I50"05. 



After adding a few facts regarding mixtures of gallium and 

 zinc, he proceeds to examine certain reactions •f the pure salts. 



1. The electric spectrum of chloride of gallium, a little con- 

 centrated, is very brilliant. The line 41 7 is much brighter than the 

 line 404. The author did not observe any other line attributable 

 to gallium ; there certainly are none of notable intensity, under 

 the conditions. The colour of the spark in chloride of gallium is 

 a beautiful clear violet. 



2. In the gas flame he got only the line Ga 041 7, and very 

 faint and fugitive, even with a salt which gave a brilliant electric 

 spectrum. 



3. The chloride and the sulphate of Ga are precipitated by 

 NHj, but the precipitate is redissolved, in great part, in an 

 excess of NH,. Taking up with HCl the portion not dissolved 

 byNHj, and recommencing the operation, all the Ga is promptly 

 obtained in ammoniacal solution. 



4. An ammoniacal solution of sulphate or chloride of Ga is 

 precipitated in the cold or hot state by an excess of acetic acid. 

 The liquor must be extremely diluted. 



5. The chloride and the sulphate of Ga are not precipitated in 

 the cold state by the add acetate of ammonia, but the reaction 

 takes place on heating. 



6. The sulphate of Ga is soluble in a 60 per cent alcohol 

 solution. 



8. A salt was obtained which the author believes to be am- 

 moniaco-gallic alum ; though, in default of sufficient quantity, he 

 was unable to analyse it or measure the angles. 



9. The alum of Ga is soluble in cold water, but, on heating, 

 the salt is decomposed, and the liquor becomes greatly troubled. 



10. This alum is not decomposed in the hot state by water 

 with addition of acetic acid. 



11. It crystallises very easily in cubes and octahedra, present- 

 ing exactly the aspect of ordinary alum ; its solution, evaporated 

 under the microscope, also presents the characteristic changes of 

 known alums. 



1 2. The crystals do not act on polarised light (between two 

 Nicols giving extinction). 



13. A small crystal was kept some time under a layer of 

 water, then transferred to a slightly supersaturated solution of 

 alumino-ammoniacal alum ; it immediately increased in jit, and 

 caused the crystallisation of the Tquor. 



14. With ammonia in excess, the alum of Ga behaves like 

 the other salts of this metal ; a portion of the oxide is precipi- 

 tated, the other portion remains in solution. 



15. The very acid solution of GajClj is precipitated by the 

 yellow prussiate. 



16. The ammoniacal solution of sulphate of Ga is decomposed 

 by the voltaic current. Metallic gallium is deposited on the 

 platinum plate serving as negative electrode. The positive elec- 

 trode is covered, at the same time, with a whitish pellicle, which 

 is easily detached from the platinum, and is insoluble in a large 

 excess of NH,. In a first operation i '6 mgr. of Ga were deposited 

 in 4h. 30m. on a platinum plate ot about 185 square millimetres 

 surface. The surface of the positive electrode was about 877 

 sq. mm. The battery consisted of five bichromate couples (zincs : 

 17 cm. X 10 cm. ) coupled in tension. The author presented to the 

 Academy a specimen weighing 3 "4 mgr. ; it was deposited in 

 5h. 40m. on a surface of about 123 to 124 sq. mm. The positive 

 electrode 877 sq. mm. ; the current furnished by ten bichromate 

 elements (as above) coupled in tension. 



17. Electrolytic gallium forms a very adherent layer; it is 

 hard ; it is polished with difficulty by friction with an agate 

 burnisher. A better polish is obtained by strong compression 

 under the burnisher ; the metal thus acquires great brightness, 

 and appears whiter than platinum. Wlien the electric current 

 and the relative dimensions of the electrodes are properly regu- 

 lated, the gallium presents a beautiful dull surface of silvery 

 white, finely granulated, and interspersed witti small brilliant 

 points, which the microscope shows to be crystals. 



18. Gallium, deposited on a platinum plate, is not much oxi- 

 dised during washing in cold or boiling water, nor on being 

 dried in free air raised to about 200°. It decomposes water 

 acidulated with HCl in the cold state, and (more rapidly ia 

 the hot state, with a brisk liberation of hydrogen. 



