562 



NATURE 



{Oct. 9, 1879 



Secretary of the Society, 11, Chandos Street, Cavendiih 

 Square, W. 



The death is announced of Prof. Mohr, of Bonn University, 

 -at the age of seventy-two. Mohr, hke his father, was originally 

 an apothecary at Coblenz. In 1864 he was attached to Bonn 

 University, and some of his works on chemistry, geology, and 

 physics have been translated into foreign languages. His activity 

 ■was inexhaustible. 



An experiment was tried on October 4 by M. Menier, in a large 

 park belonging to him at Noyelles, on the banks of the Mame, 

 -about 50 kilometres from Paris, on the Eastern Railway. A 

 part of the water power which he uses for his workshop 

 operates on eight ordinary Gramme machines producing the 

 current for the Serrin regulators or Jablochkoff candles. The 

 current of two of these machines was sent into the park at a 

 distance of 7CX3 metres, where two others had been arranged on 

 s. truck and connected with a plough by a dragging rope. A 

 number of furrows were then traced with this simple apparatus, 

 and have been found equal to the work of four oxen. The 

 experiment has been found so successful that M. Menier intends 

 ^levoting a water-power of thirty horses to agricultural work 

 round his workshop. He intends using water-pipes for placing 

 his insulated copper wires, and expects to conduct his power 

 to 5 kilometres from his mill in every direction, so to perform 

 ■various agriciJtiu'al operations on a surface of more than ten 

 square miles. 



Three diiiferent telephonic companies are competing in 

 Paris, viz., the Gower (magnetical). Bell, and Edison, the two 

 latter working with the microphone. It is said that the Bell 

 and Edison Companies will enter into a working arrangement, or 

 a fusion. 



The city of Lille, in French Flanders, sends every year to 

 England the best English scholars of the Municipal School. 

 This year the journey made at the expense of the city has taken 

 -unprecedented extension. The number of travelling pupils was 

 twenty-three, and the excursion occupied a fortnight, during 

 which not only London, but Edinburgh, Dundee, Glasgow, 

 Newcastle, Durham, and York were visited. 



The tramway from Naples Observatory to the foot of the cone 

 ■of Mount Vesuvius is nearly completed, and will be opened 

 early next year. A steam-engine at the summit will draw the 

 ■trams up by a windlass on Spielg's system. 



We understand that by the retirement of Dr. Gilchrist from 

 the charge of the Crichton Asylum at Dumfries, a very important 

 and valuable appointment is now open to the psychological 

 branch of the medical profession. 



A Faculty of Medicine has been created at Bordeaux. M. 

 Ferry, the Minister of Public Instruction, will be present at the 

 -ceremony of laying the first stone. 



The French Minister of War has published a regulation for 

 organising optical telegraphy in time of peace. The several places 

 on the French frontier are to be connected by posts ; apparatus 

 ■are to be manoeuvred by persons trained and keeping records of 

 <;ommunications sent or received. This new service is to be 

 placed under the supervision of the Director of Aerial Com- 

 munications, who already has command of the balloonists and 

 the colombophiles for carrier-pigeons. 



The Times Geneva correspondent states that a fisherman has 

 ^ound a very remarkable weapon near the lake-dwelling of 

 Locras, in the Lake of Brienz. It is a double battle-axe of pure 

 copper, forty-two centimetres long, and weighing three kilo- 

 grammes. Massive and heavy in the middle, it broadens out 

 gradually into two cutting edges, each having a width of twelve 



centimetres. It has been added to the collection of Dr. Gross, 

 at Neuveville. Several similar weapons have been found in 

 Denmark ; but, so far as is known, this is the first of the kind 

 discovered in Switzerland. The lake-dwelling of Locras is 

 assigned by archaeologists to the age of stone. 



At Trier (Treves) a fresh discovery of colossal remains of 

 Roman structures has recently been made. They consist mainly 

 of a large wall, i '88 metres thick, with two other ones running 

 parallel to it and only 90 centimetres apart. Between the latter 

 two, at a depth of 8 metres below the present surface of the 

 ground, there is a vaulted canal, and a little further on an 

 enormous cellar vault. The foundations of the two parallel walls 

 have in some parts not been reached at a depth of 9 metres. 

 Archaeologists are at present at a loss to know what may origi- 

 nally have been the nature of the structure, as nothing at all 

 resembling it has ever been discovered. 



We have received from the Dundee Naturalists' Society very 

 satisfactory reports of the work done during the sessions 

 1877-8-9. 



In a recent communication to the Vienna Academy, on the 

 cause of excitation of electricity in contact of heterogenous 

 metals. Prof. Exner offers proof that the electromotive force is 

 always in direct relation to the heat of combustion of the metals 

 in question, provided they are in air. Such proof is quantita- 

 tively furnished for the combinations of Zn, Cu, Fe, and Ag, 

 with Pt. Further it is shown that the so-called contact-force of 

 two metals changes, whenever these are no longer in air, but in 

 some gas acting in a different way on them chemically. Nuiae- 

 rical proof of this is given in the case of Ag, according as this 

 metal is in air or in an atmosphere of chlorine. Since the 

 numerical values obtained in this research, for the contact -force, 

 as also the few older determinations are in full harmony with 

 the chemical theory of this mode of electric excitation, and the 

 experiments are contrary to the voltaic theory, the author 

 considers further adherence to the latter impossible. 



The radicles of seeds lying on the [surface of the ground 

 penetrate into the ground only under certain conditions. Ac- 

 cording to recent observations by Dr. Richter, of Vienna, these 

 are of the following nature ; — I. The penetration takes pkice 

 only when the temperature exceeds a certain minimum above 

 the lower zero of germination, depending on the species of 'ihe 

 plant. 2. This minimum is much lower, for one and the same 

 plant species, if the seedling is exposed to light, than if it is 

 kept in darkness, the reason being that in the former case a trans- 

 formation of light into heat occurs (as shown by experiments of 

 cultivation at temperatures above the optimum of germinating 

 temperature of particular plants). 3. A pressure of the roots 

 on the ground, whether through formation of root-hairs, or from 

 external causes, favours the penetration of the roots. 4. The 

 nature of the ground affects the penetration of roots, only in that 

 the latter occurs more easily the less resistance the ground pre- 

 sents to the roots. 5. Geotropism is naturally concerned most 

 largely in the penetration of the roots. The light affects it in 

 so far as by production of heat, it favours the growth generally, 

 and therewith the geotropic downward bending. On the other 

 hand, negative heliotropism is (contrary to expectation) not con- 

 cerned in penetration of illuminted roots into the ground. 



The Rouen joiu-nals report an invasion of swarms of bees in 

 several houses of the town. In a confectioner's establishment 

 legions of these bees took possession, making it impossible for 

 the workmen to continue their occupations. Nearly every in- 

 mate of the place was stung, and one person was maltreated so 

 severely that medical aid had to be called in. An attempt was 

 made to get rid of these importunate guests by burning sulphur 

 to asphyxiate them, but the bees took refuge in the upper storeys 



