RESEARCHES AND EXPERIMENTS. 



725 



sus is of a silky texture and very tough, and ex- 

 periments have shown that it is well adapted 

 for spinning. But again the question of sup- 

 ply occurs, and it is difficult to see how a suffi- 

 cient quantity of the byssus can be obtained 

 at prices which would enable the material to 

 compete with silk. Nevertheless, it must be 

 borne in mind that greater difficulties than 

 these have been successfully overcome. If the 

 commercial value of the new material were 

 fully demonstrated, there is no doubt that some 

 means of increasing the supply of the byssus 

 would be devised. 



The Shotts of Algeria. M. de Lesseps, who 

 lately returned from a visit to Tunisia, has given 

 to the Paris Academy of Sciences an account 

 of the work being done by Roudaire in survey- 

 ing the region of the Shotts. M. Roudaire is 

 accompanied by two engineers, a physician, a 

 purser, a draughtsman, and twelve chasseurs 

 d'Afrique. M. de Lesseps is quite satisfied 

 that there exist indisputable evidences of the 

 former presence of the sea in the Shotts. The 

 region around, now a sandy desert, is dotted 

 all over with Roman ruins, going to show that 

 the locality was once inhabited by a thrifty 

 population. One of the most remarkable of 

 the ruins is that of a structure that might bear 

 comparison with the Coliseum of Rome. It 

 was erected by Gordianus, proconsul of Africa, 

 who at the age of eighty years (A. D. 238) was 

 compelled by the leaders of a local rebellion 

 to assume the imperial title. 



Atmospheric Electricity and Plant-Life. 

 Experiments made by Grandeau go to show 

 that atmospheric electricity is a powerful agent 

 in promoting assimilation in plants. He finds 

 that plants defended from the atmospheric elec- 

 tricity build up 50 to 60 per cent, less of nitro- 

 genized matter than those exposed to it. The 

 proportion of ash is higher and that of wa- 

 ter lower in plants sheltered from atmospheric 

 electricity. The electric screen inclosing the 

 plants experimented on was formed of four 

 triangles of iron. The plants were maize, tobac- 

 co, and wheat; all other conditions remained 

 natural, but of the two specimens pitted against 

 each other, one was screened from atmospheric 

 electricity and the other was not. The plants, 

 after being allowed to grow for several months, 

 were measured, weighed, and analyzed. All 

 the experiments exhibited the above percentage 

 in the most striking manner. The plants test- 

 ed were tall, but low-growing plants are equally 

 influenced by atmospheric electricity. This fact 

 may serve to explain the absence of herbage 

 under certain trees. It should also be men- 

 tioned that the total development of the plant 

 is proportional to that of the nitrogenized mat- 

 ter, as in growth under normal conditions. 

 These results are confirmed by the researches 

 of Berthelot, who in a note to the Paris Acad- 

 emy of Sciences draws attention to the discov- 

 ery made by him that free nitrogen unites itself 

 to organic matter under the action of electric 

 currents not only from ordinary induction coils, 



but from feeble voltaic batteries for example, 

 five Leclanch6 cells ; the pr.oportion of nitro- 

 gen thus fixed in seven months on paper arid 

 dextrine being 1-92 thousandths, which will 

 represent about T2 hundredths of matter analo- 

 gous to the nitrogenized compounds of vegeta- 

 bles. It would thus appear that the slow, con- 

 tinuous action of feeble atmospheric currents 

 on vegetation has a far more important bearing 

 on agriculture than the formation of nitrous 

 and nitric acid with their ammonaical salts by 

 the violence of the lightning-flash. 



A Registering Sounding Apparatus. Lieu- 

 tenant Pinheiro, of the Brazilian navy, has 

 invented an instrument which gives a delinea- 

 tion of the bottom of the sea. It has received 

 the name of sondograph. It is suitable only 

 for sounding undulating bottoms, such as the 

 shifting sand-banks and shoals of the mouths 

 of Brazilian rivers, and is not designed for 

 rocky or broken ground. It is composed of 

 an indicator which takes cognizance of the 

 contour of the bottom, and a register furnishes 

 a graphical trace of it. The indicator is formed 

 of a wooden stem, fitted at its lower extremity 

 to a hollow roller, which rolls upon the bot- 

 tom, and retains specimens of it for examina- 

 tion. This stem is articulated at its upper ex- 

 tremity around a horizontal axis, which carries 

 a graduated arc intended to show the different 

 inclinations that it takes for the given levels 

 of the bottom, which depend on the versed sines 

 of these angles. On the same axis is a toothed 

 wheel, which by a pinion and eccentric com- 

 municates a rectilinear movement to a style, 

 which traces over a band of paper put in move- 

 ment by a chronoinetric motor a continuous 

 curve, which gives in this way the graphical 

 relation of the changing levels and the speed 

 of the ship. As the direction and speed of the 

 ship can readily be determined, a section show- 

 ing the soundings along the ship's route can 

 be plotted. M. Pinheiro's sondograph may 

 become useful in hydrographical work at the 

 mouths of rivers subject to sand-bars and shift- 

 ing channels. 



New Photographic Process. A new pho- 

 tographic process, invented by Deyrolle, sub- 

 stitutes sensitized paper for the heavy, brittle 

 plates of glass at present in general use, and 

 hence it is specially suited for tourists and 

 travelers. In this process the paper for the 

 negatives is covered with a special coating 

 insoluble in ether, alcohol, or water, and hence 

 it undergoes all the operations of photography 

 without change. Besides being quite equal to 

 glass plate, this paper possesses sundry advan- 

 tages of its own. First, the layer of collodion 

 is so firmly attached to the coating of the paper 

 that it can not be injured by contact with a 

 hard object, or even by slight friction. Then, 

 the picture can be developed by total immer- 

 sion in the developing liquid, instead of pouring 

 the latter on the collodion layer, as in the case 

 of plates of glass an operation which requires 

 some dexterity and long practice. This paper 



