November 30. 1899] 



NATURE 



113 



one-hundred-millionth of a second after the discharge of the 

 condenser. MM, Abraham and Lemoine have also succeeded 

 in showing Kerr's phenomenon for a conducting liquid. The 

 Kerr's condenser, hiving water between its two armatures, is 

 arranged in the circuit connecting two ordinary condensers in 

 series. On discharging these by the spark used as the source 

 of light the charges liberated instantaneously charge the plates 

 of the Kerr's condenser. For a very small interval of time the 

 water is affected in the same way as a dielectric, and on ob- 

 serving the analyser a brilliant reappearance of light establishes 

 the existence of the phenomenon. 



In the Bulletin International o{\heCrAcovi Academy, M. P. 

 Rudski continues his papers on the elastic properties of 

 rocks. It would appear that even such rocks as granite cannot 

 be regarded even " grosso modo " as isotropic ; but the expres- 

 sion for the elastic potential generally involves five constants. 

 There are no grounds for assuming the separate propagation of 

 dilatational and torsional waves in gneiss, granite and similar 

 rocks ; on the contrary, the actual waves are partly torsional 

 and partly dilatational. 



The Mineralogical Magazine, vol, xii.. No. 56, which has 

 just appeared, contains a description of a new three-circle 

 goniometer designed by Mr. G. F. H. Smith, and intended 

 for comparatively rapid measurements of the geometrical con- 

 stants of crystals and the indices of their faces. The paper 

 c;ives a historical account of the one-circle goniometer of 

 Wollaston, the two-circle or " theodolite " goniometer of Miller, 

 and then describes the new instrument, which is a combination 

 of those forms. The great advantage of the combination is that 

 the crystal is adjusted once for all. The measurements may 

 be made in any desiied zone, the orientation of which is at 

 once determined. For crystals small enough to be firmly held 

 by wax in all positions, the most convenient arrangement is to 

 give all three motions to the crystal ; but, if necessary, the 

 telescope and collimator may have one or more. 



Three noteworthy papers on the cultivation and manufacture 

 of tobacco have recently appeared. One of these publications 

 is Report No. 60 of the U.S. Department of Agriculture, and 

 in it Mr. Milton Whitney and Mr. T. H. Means describe their 

 investigations upon the temperature changes in fermenting 

 tobacco in Florida and Connecticut. The report also comprises 

 a risume of Dr. Oscar Loew's investigations of the cause of 

 fermentation, which throw light upon and explain the observed 

 temperature changes, and the necessity of maintaining a de- 

 finite amount of moisture in the tobacco during the curing and 

 fermentation. In another paper (Report No. 62), published by 

 the U.S. Department of Agriculture, Mr. Marcus Floyd 

 describes the cultivation of cigar-leaf tobacco in Florida, where 

 striking developments of the tobacco industry have taken place 

 in recent years. The object of collecting information of this 

 kind is to investigate whether the crops produced on the 

 various types of tobacco soils are the best obtainable with the 

 present state of knowledge and skill in manipulation. In this 

 way the Department of^Agriculture is making a scientific study 

 of the possibilities of the improvement and extension of an 

 important industry. The third paper mentioned, on the cul- 

 tivation and manufacture of tobacco, appears in the Kevue 

 Ginirale des Sciences for October 30, and is accompanied by a 

 map showing the districts in which tobacco is cultivated in 

 France. 



"The Geology of the Country around Dorchester" is the 

 title of a Memoir (price \s.) just issued by the Geological 

 Survey in explanation of the new series map, No. 328. The 

 NO. 1570, VOL. 61] 



Memoir is written by Mr. Clement Reid, and it deals mainly 

 with the chalk, eocene strata and drift. Among the more 

 interesting natural features in the region are the numerous 

 swallow-holes on Tuddletown Heath and adjacent tracts. Per- 

 haps the largest is that known as Cull-pepper's Di.sh, a hollow 

 about one hundred yards long and forty feet deep. Another is 

 known as Hell Pit. Altogether there are some six hundred of 

 these pits, due to the di.-solution of the chalk and the sub- 

 sidence of superincumbent tertiary deposits. Mr. Reid points 

 out that the lower tertiary (Reading) beds consist locally of 

 sands with impersistent beds of clay. The rainfall readily 

 sinks into the porous ground until arrested by one of the clay- 

 bands, and these guide the water in particular directions, 

 whence it descends and dissolves the chalk. The Reading beds 

 and London clay vary considerably from their equivalents else- 

 where, the London clay consisting largely of sand and sandy 

 loam. The Bagshot beds furnish evidence of true river-deposits 

 which replace the more estuarine strata of the eastern part of 

 the Hampshire basin. Large pits near Moreton station show 

 (beneath plateau gravel) Bagshot beds comprising current- 

 bedded sand, pipe-clay and gravelly seams containing chalk- 

 flint, Greensand chert, Purbeck limestone, Radiolarian chert, 

 and Schorl-rock. Here, in fact, are found fragments of all the 

 rocks which occur further west in gravels which have been 

 regarded as drift, but which Mr. Reid considers, with good 

 reason, to be of Bagshot age. The accounts which he gives of 

 these and other deposits will be read with interest. Among the 

 latter we may mention the Pliocene formation at Dewlish, the 

 clay-with-flints, plateau gravels, and more recent deposits. 



Some interesting experiments on the rate of multiplication of 

 various yeast cells have been carried out by Dr. D. P. Hoyer, 

 of Vienna, and are published in the Centralblatt fiir Bakteri- 

 ologie. Part ii., No. 21. The author has determined the time 

 required at different temperatures, 13° C. and 20° C. and 25° C. 

 respectively, by various yeasts to produce a new generation from 

 a parent cell. Thus at 13° C, S. ellipsoideus I. Hansen re- 

 quires nine hours and four minutes, and at 25" C. six hours and 

 twelve minutes ; .S". tnembranae-faciens at 13° C. seven hours 

 and one minute, and at 25° C. five hours and thirteen minutes 

 to form a new generation. At 6° C. it appears that the majority 

 of the yeasts investigated did not, even after a week, produce a 

 new generation, and the experiments conducted at this temper- 

 ature were discontinued. The yeasts thus so closely scrutinised 

 were grown on gelatine, and were not more than from three to 

 four days old. Many bacteria have been submitted to similar 

 observations ; but until these experiments, made by Dr. Hoyer, 

 were published, scarcely any investigations of this kind, in 

 regard to yeasts, have been recorded. 



The Bulletin of Miscellaneous Information (Trinidad) for 

 October contains a fuller diagnosis of the new fungus-parasite 

 of the cacao-plant, A'ifc/r/a Bainii, Mass. It seems, however, 

 still doubtful whether it is the cause of the disease, or simply 

 saprophytic. 



In the number ot the Agricultural Gazette of New South 

 Wales for October is a very interesting further account, by Mr, 

 J. II. Maiden, of a -botanical visit to Mount Kosciusco, The 

 flora presents some Alpine features, but the flowers are not 

 specially large or brilliant. There is an extraordinary pre- 

 dominance of white flowers, almost exactly one-half of those 

 gathered at high altitudes. The flora presents, on the whole, a 

 strong affinity with that of Tasmania. A list of the plants 

 collected is appended. 



The Journal of the Royal Horticultural Society for 

 November, besides purely horticultural papers, contains several 



