56 



SCIENTIFIC NE^A/S. 



Qan. 20, iS88. 



give the following results as to the resistance of the sub- 

 joined species of wood to electric currents passed along 

 the fibre : 



Mahogany . . . . . . 4° meg- ohms. 



Pine . . . . . . . . 214 „ 



Rosewood . . . . . . 291 „ 



Beech . . . . . . . . 397 „ 



Oak 478 „ 



Teak 734 



If the direction of the current is transverse to the fibres 

 the resistances are increased from 50 to 100 per cent. 



Influence of the Moon on the Barometer. — M. A. 

 Poincare has recently presented a note to the French 

 Academy of Sciences, in which he has drawn attention to 

 the variations in the height of the barometer with the 

 phases of the moon. He has considered the data for the 

 year 1S83 for the parallels 40° and lo*^ north, and has 

 shown that there appears to be some relationship 

 between the atmospheric pressures in these two latitudes 

 and the varying positions of the moon. Should he be 

 able, from the determinations of barometric pressure, to 

 generalise some law connecting these phenomena, we 

 may hail this fact as a valuable contribution to our 

 present knowledge of meteorology. 



Carbons for Electric Lighting. — As an indication of 

 the great development of electric lighting in the United 

 States, it is stated that there are 150,000 carbons used 

 daily in that country, and that 100,000 are manufactured 

 at Cleveland, where there are twenty furnaces. The 

 carbons are made from the residua of petroleum distilla- 

 tion, as well as from the carbonaceous deposits found 

 around natural gas wells. The materials are finely 

 pulverised, mixed with a little pitch, and placed in 

 moulds, which are packed in boxes and put into a fur- 

 nace, where they are submitted to an intense heat for 

 five days. One furnace holds about 45,000 carbons, and 

 two furnaces are constructed side by side, so that one 

 can be charged while the other is being heated. 



The Manufacture of Starch. — In addition to the 

 manufacture of spirits and sugar, an important industry 

 which is rapidly increasing in the eastern provinces of 

 Germany is the production of potato starch. In 1883 

 the production of starch in the province of Posen 

 amounted to 11,000 tons; in 1884,10 12,500 tons; in 

 1885, to 19,000 tons; and in 1886, to 23,500 tons; show- 

 ing an increase of over 100 per cent, in a very short 

 period. The greater portion of the starch is exported 

 via Stettin, and large quantities are also sent to works 

 in the province of Brandenburg. At present consign- 

 ments of starch to the western districts of Germany are 

 prevented by the high railway tariffs, and were these 

 reduced it would allow of a still further development of 

 the industry. 



Sinking Shafts in Wet Sand. — M. Alexandre, of the 

 Houssu Company, in Belgium, is sinking a mine shaft 

 through a stratum of moist sand 12 metres thick, met 

 with at 70 metres depth, by the Poetsch method of 

 freezing the sand and then excavating it like rock. Ten 

 iro.i tubes (with cutting crown) have been inserted in the 

 sand at intervals of about i metre, penetrating the coal 



belovi?. Into these are put other tubes, through which is 

 passed a solution of chloride of magnesium, cooled by the 

 ammonia freezing process to a temperature of 14°. C. The 

 sand is frozen more than 3 metres round the tubes. It 

 has the appearance of a rock harder than the compact 

 chalk of the English Channel tunnel ; it is sparkling, and 

 speckled with particles of coal. In making a tunnel 

 recently at a small depth under part of the city of 

 Stockholm, this method was employed with great success. 

 — Annates Industridles. 



Influence of Sugar upon Cement. — The results ot 

 some experiments made by Mr. Parsons on the influence 

 of sugar on both natural and manufactured cements 

 were given in a paper which he read before the recent 

 meetingof the American Society of Mechanical Engineers. 

 The tests carried out by him were made to conform to 

 the system recommended by the committee of the 

 American Society of Civil Engineers. The machine 

 used was a Riehle Brothers standard cement tester, the 

 form of the mould and the shape of the jaws being those 

 adopted by the above committee. Mr. Parsons found 

 that the reason why sugar gives increased strength to 

 the cement is more mechanical than chemical. That is 

 to say, the sugar, by its presence in the briquette, 

 appears simply to retard the setting of the cement, and 

 thereby permits the chemical changes in the cement to 

 take place more perfectly. He added that the addition 

 of sugar gave an increased efficiency of about 15 per 

 cent. 



Structure of Muscle. — The " Structure of Muscle," 

 one of the most difficult questions in histological research, 

 is the subject of an essay by Mr. C. F. Marshall, of 

 Owens College, who gives the following summary of his 

 researches. In all muscles which have to perform rapid 

 and frequent movements, a certain portion of the muscle 

 is differentiated to perform the function of contraction, 

 and this portion takes on the form of a very regular and 

 highly specialised intra- cellular network. This network, 

 by its regular arrangement, gives rise to certain optical 

 effects, which cause the peculiar appearances of striped 

 muscle. The contraction of the striped muscle fibre is 

 probably caused by the active contraction of the longi- 

 tudinal fibrils of the intra-cellular network ; the transverse 

 networks appear to be passively elastic, and by their 

 elastic rebound cause the muscle to rapidly resume its 

 relaxed condition when the longitudinal fibrils have 

 ceased to contract ; they are possibly also paths for the 

 nervous impulse. In some cases where muscle has 

 hitherto been described as striped but gives no appear- 

 ance of the network on treatment with the gold and 

 other methods, the apparent striation is due to optical 

 effects caused by a corrugated outline in the fibre. In 

 muscles which do not perform rapid movements, but 

 whose contraction is comparatively slow and peristaltic 

 in nature, this peculiar network is not developed. In 

 most, if not all, of the invertebrate unstriped muscle there 

 does not appear to be an intra-cellular network in any 

 form, but in the vertebrate unstriped muscle a network 

 is present in the form of longitudinal fibrils only. This 

 possibly represents a form of network intermediate 

 between the typical irregular intra-cellular network of 

 other cells and the highly-modified network of striped 

 muscle. The cardiac muscle-cells contain a network 

 simiar to that of ordinary striped muscle. — Lancet, 



