Dec. 12, 1878] 



NATURE 



^n 



which the greatest part of the Berlin press has assumed with 

 re<i'ard to the doctrine of evolution must be attributed to 

 thfs authority. But much as we mu-t regret the reactionary 

 current in this and other intelligent Berlin circles, yet we 

 mast point out that by this evil we are guarded from a far 

 greater one. This greater, indeed the greatest, evil which could 

 befall German science would be a Berlin ' monopoly of knowledge,' 

 the centralisation of science. What highly disastrous fruit this 

 centralisation has borne in France, for instance ; how the Paris 

 'monopoly of knowledge' causes a constant degradation of 

 French science, and has led it downwards from the greatest 

 heights for the last half-century, is well known. Probably the 

 wide-spread differentiation and the many-sided indi\'iduality of 

 the German national spirit, the often-decried German particu- 

 larism, will save us from a centralisation of science of this kind, 

 which particularly in our capital, Berlin, would be doubly dan- 

 gerous. Little as our * small states ' could be politically of any 

 diuration or could lead to a useful state-form, they have certainly 

 been most beneficial and fertile for German science. Because 

 this" owes its principal advantages over others to the numerous 

 little centres of education, which the capitals of the German 

 small states formed, and to the many little universities which 

 were always in healthy competition with one another. Let us 

 hope that this beneficial decentralisation of science in our poli- 

 tically united Fatherland will continue permanently. Next to 

 the centrifugal striving of our German national spirit, nothing 

 will further this object so much as an energetic resistance to the 

 free progress of science, just as now again it begins to show 

 itself in the capital of the empire. Because at the same rate as 

 this will remain behind in the mighty current of free and unim- 

 peded mental progress, other numerous centres of education in 

 Germany which follow this current enthusiastically, or at least 

 willingly, will outrun it." 



" If Emil Dubois Reymond wanted to make his 'Ignorabi- 

 mus ' the watchword of science, and Rudolf Virchow his still 

 further-reaching ' Restringamur,' then from Jena and from a 

 hundred other educational centres they are met with the call — 



" Impavidi progrediamur 1 "' 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 



Students of Natural Science v.ho would much rather know 

 French and German than Greek will be glad to learn that a very 

 strong memorial against the retention of Greek as a subject for 

 sdl honour candidates has been presented to Cambridge Uni- 

 versity. It is signed by ten heads of public schools, including 

 Drs. Hornby (Eton), Butler (Harrow), and Abbott (City of 

 London), Messrs. Matthew Arnold, Carlyle, W. E. Forster, the 

 Bishops of Exeter and Manchester, Dean Cowie, Dean Stanley, 

 and Dr. Vaughan, Prof. Jebb, and Mr. Roby, to say nothing of 

 such bulwarks of science as Mr. Darwin, Prof. Huxley, Sir 

 Joseph Hooker, Mr. Spottiswoode, and Prof. Tjmdall. 



, The Board of Musical Studies at Cambridge have applied for 

 tiie appointment of a University Reader in Acoustics, 



• The sum in the hands of the Sedgwick Memorial Committee 

 for the erection of a new building for the geological collection is 

 12,000/., not 1,200/. as we stated last v.eek. 



King's College (London) Magazine, No. 5, vol. ii. of which 

 has been sent us, contains some pleasant reading, but no one 

 would infer from its contents that the College was an important 

 centre of scientific instruction and research. 



Dr. J. CossAR EwART has been appointed by the Crown to 

 the Chair of Natural History in the University of Aberdeen. 



Mr. F. Guthrie, formerly of Graaf-Reinet College, has been 

 appointed to the Chair of Mathematics at the South African 

 College, Capetown. 



The Journal de St. Petershourg gives the following particulars 

 concernmg the public provision for education in Russia :— The 

 sum assigned in the Budget of this year for education is 

 15,971,289 roubles (about 2,395,000/.). There are eight Uni- 

 versities (not reckoning that of Helsingfors for Finland^ with 

 5,629 students. Of these 85 are divinity students, 583 belong 

 to the philological faculty, 1,629 to the faculty of law, 30 to 

 Uiat of Eastern languages, 622 to the mathematical faculty, 550 

 to that of natural science, and 2,130 to the medical faculty. 

 Ihere are 53 ecclesiastical seminaries, with 12,227 pupils; 195 

 gymnasia and pro-gymnasia, with 50,701 pupils: "56 middle- 

 class schools, with 10,888 scholars. There are 19 mUitary 



gymnasia, but the number of pupils is not given. For females 

 there are 223 gymnasia and pro-gymnasia, having 34,878 pupils ; 

 and this does not include the many institutions which are sub- 

 ject to the control of the Fourth Division of the Imperial Chan 

 cellery. There are 68 normal schools and training colleges for 

 teachers, having 4,968 students. There are 10 other such insti- 

 tutions supported by non-public funds. The number of elemen- 

 tary schools in operation this year is 25,491, with 1,074,559 

 pupils. 



SOCIETIES AND ACADEMIES 

 London 

 Royal Society, December 5. — " On the Illumination of 

 Lines of Molecular Pressure, and the Trajectory of Molecules," 

 by WiUiam Crookes, F.R.S., V.P.C.S. 



Induction Spark through Rarefied Gases. Dark Space round 

 the Negative Pole 

 The author has examined the dark space which appears round 

 the negative pole of an ordinary vacuum tube when the spark 

 from an induction coil is passed through it. He describes many 

 experiments with different kinds of poles, a varying intensity of 

 spark, and different gases, and arrives at the following propo- 

 sitions : — 



Illumination of Lines of Molecular Pressure 



a. Setting up an intense molecular vibration in a disk of 

 metal by electrical means excites a molecular disturbance which 

 affects the surface of the disk and the surrounding gas. With a 

 dense gas the disturbance extends a short distance only from the 

 metal ; but as rarefaction continues, the layer of molecular dis- 

 turbance increases in thickness. In air at a pressure of '078 mm. 

 this molecular disturbance extends for at least 8 nam. from the 

 surface of the disk, forming an oblate spheroid around it, 



b. The diameter of this dark space varies with the exhaustion ; 

 with the kind of gas in which it is produced ; with the tempera- 

 ture of the negative pole ; and, in a slight degree, with the 

 intensity of the spark. For equal degrees of exhaustion it is 

 greatest in hydrogen and least in carbonic acid, as compared 

 with air. 



c. The shape and size of this dark space do not vary with the 

 distance separating the poles ; nor, only very slightly, with 

 alteration of battery power ; nor with intensity of spark. When 

 the power is great the brilliancy of the unoccupied parts of the 

 tube overpowers the dark space, rendering it difficult of obser- 

 vation ; but, on careful scrutiny, it may still be seen unchanged 

 in size, nor does it alter even when, with a very faint spark, it 

 is scarcely visible. On still further reduction of the power, it 

 fades entirely away, but without change of form. 



The author describes numerous experiments, devised to asca-- 

 tain if this visible layer of molecular disturbance is identical 

 with the invisible layer of molecular pressure or stress, the 

 investigation of which has occupied him for some years. 



The Electrical Radiometer 



One of these experiments is as follows : — An ordinary radio- 

 meter is made, with aluminium disks for vanes, each disk coated 

 with a film of mica. The fly is supported by a hard steel cup 

 instead of a glass cup, aad the needle point on which it works 

 is connected by means of a wire with a platinum terminal sealed 

 into the glass. At the top of the radiometer bulb a second 

 terminal is sealed in. The radiometer can therefore be con- 

 nected with an induction coil, the movable fly being made the 

 negative pole. 



Passing over the phenomena observed at low exhaustions, the 

 author tinds that, when connected with the coil, a halo of a 

 velvety violet light forms on the metallic side of the vanes, the 

 mica side remaining dark throughout these experiments. As the 

 pressure diminishes a dark space is seen to separate the violet 

 halo from the metaL At a pressure of half a millimetre this 

 dark space extends to the glass, and positive rotation commences. 



On continuing the exhaustion the dark space further widens 

 out and appears to flatten itself against the glass, and the rota- 

 tion becomes very rapid. 



When aluminium cups are used for the vanes, instead of disks 

 backed with mica, similar appearances are seen. The velvety 

 violet halo forms over each side of the cup. On increasing the 

 exhaustion the dark space widens out, retaining almost exactly 

 the shape of the cup. The bright margin of the dark space 

 becomes concentrated at the concave side of the cup to a lumi- 

 nous focus, and widens out at the convex side. On further ex- 

 haustion the dark space on the convex side touches the glas.^ 



