April 6, 1905] 



NA TURE 



547 



In Fig. 6 is siiown ths Wehnelt interrupter. A large rect- 

 angular glass vessel containing dilute sulphuric acid is 

 fitted with an ebonite cover, E c, which supports the elec- 

 trodes. The terminal t, is in connection with the lead 

 plate, L V, which forms the kathode. The bridge-piece, B, 



RY CURRENT 



supports two rack rods, r, and the anode terminal t,. Each 

 rack rod is geared with a pinion by means of which it 

 may be raised or lowered as required, m ii being the milled 

 heads for turning the pinions. The rack rods are continued 

 <lo\vnwards in tine form of thinner rods encircled by glass 



Fig. 5. 



tubes, G T, and finally end in stiff platinum points, p p, around 

 which the tapered ends of the tubes fit very closely. By 

 raising or lowering either anode, a smaller or greater surface 

 of it may be exposed to the surrounding electrolyte. The 

 densitv of the acid depends on the voltage at which the 



interrupter is to be supplied. The interrupter is connected 

 in series with the primary of the induction coil, and, if 

 necessary, with an additional self-inductance. As soon as 

 the circuit is closed, and provided the area of anode surface 

 exposed to the electrolyte is not excessive, and the self- 



NO. 1849, VOL. 71] 



inductance not too small, the interrupter begins to act. A 

 pink glow appears around the extremities of the anodes, the 

 interrupter emits a loud note of definite pitch, and a shower 

 of sparks is produced across the space between the secondary 

 terminals of the coil. Bubbles of gas rush up each glass 

 tube, G T, the electrolyte rises in each tube, and may overflow 

 through the side openings, o. 



Another form of electrolytic interrupter, originally due to 

 Caldwell, but subsequently improved and moditied in various 

 ways by others, is shown in Fig. 7. The terminal t, is, 

 as in the Wehnelt interrupter, connected to a lead plate. 

 But instead of a platinum anode, a lead plate is also used 

 for the other electrode. This second lead plate is surrounded 

 by a glass tube, G t, which completely separates it from the 

 remainder of the electrolyte except for a small perforation 

 at the bottom of the tube, through which passes the pointed 

 end, p, of a long glass rod, g, supported in a tubular rack 

 rod,' R, which may be raised or lowered by means of a, pinion 

 fitted with the milled head, M H. The area of communication 

 between the electrolyte in the tube and that outside is con- 

 trolled by raising or lowering the conical glass plug. Either 

 electrode may be used indifferently as anode or kathode. 

 The break takes place at the perforation of the glass tube. 



In conclusion, thanks must be expressed to Mr. k. C. 

 Cossor, of 54 Farringdon Road, E.C., who very kindly 

 provided an induction coil and a number of interrupters 

 required to carry out the tests recorded in this article. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



It is stated that Sir William MacDonald, of Montreal, 

 has decided to give 800,000/. toward the erection of a 

 normal school at St. Anne de Bellevue, a few miles distant 

 from Montreal, and the erection and endowment of an 

 agricultural college at the same place. 



There is no sign of diminution in the interest shown 

 by public authorities and bv private benefactors for higher 

 education in the United States. We learn from Science 

 that by the will of Mrs. Stanford about 400,000/. is be- 

 queathed to Leland Stanford Junior University. The uni- 

 versity also comes into possession of the house built by 

 Senator Stanford at San Francisco and its contents, which 

 are valued at more than 400,000/. The legislature of 

 North Carolina has appropriated 10,000/. for the erection 

 of a chemical laboratory at the University of North 

 Carolina. 



We have received a copy of the prospectus of courses 

 of instruction in poultry-keeping held at University College, 

 Reading, and the college poultry farm at Theale. The 

 farm, v/hich is of about 40 acres, largely meadow land, is 

 used also as an experimental station. The courses are of 

 varying lengths and different degrees of difficulty to meet 

 the' requirements of all grades of students. The practical 

 work is exhaustive, and due attention is given to kindred 

 technical subjects such as carpentry. It appears that this 

 branch of the work of the college has had an important 

 influence on the development of scientific poultry-keeping 

 in Berkshire and neighbouring counties. 



A strong committee has been formed for the purpose of 

 securing suitable conditions of work, and providing oppor- 

 tunities for development, of Bedford College for Women in 

 London. An appeal to the public on behalf of the college 

 has just been issued. The college, which is a school of 

 the University of London, must before long come to an 

 end unless it can obtain a large amount of public support. 

 A freehold site and a new building are essential, and it is 

 estimated that their cost mav amount to 150,000/. Ex- 

 perience has shown that the fees of the students and the 

 allotted share of the Treasury grant to university colleges 

 are not sufficient without considerable additional support 

 to carry on the higher education supplied by the college, 

 (he cost of which is constantly increasing. To make the 

 work of the college fully effective, it is therefore desirable 

 to obtain further endowment to the extent of 100,000/., or 

 the equivalent income. The Senate of the University of 

 London has shown approbation of the scheme for re- 



