502 



SCIENTIFIC NEV/S. 



[May 25, 18 



and is provided with a roller and rope for inclining the 

 aerostat. The vessel is propelled and steered by wheels 

 working in a casing having valves connected by a lever. 

 Electric motors driven by accumulators are arranged on 

 the shaft of each wheel. A tube is passed through the 

 cylinder, and air is admitted between it and the cylinder 

 to assist in resisting the atmospheric pressure. The 

 vessel is lowered by charging the cylinder with air. 



Steel Pens. — Mr. L. M. H. M. Dahms has patented 

 an apparatus for renovating steel pens. The apparatus 

 consists of two pieces, one of which has an angle-shaped 

 cross section, while the other has a U-shaped one. One 

 side of each piece has a projection to carry a pin, by 

 which the two pieces are hinged together and around 

 which they can rotate. The inner faces of both the 

 angle-shaped and U-shaped are roughened. Near one end 

 of the U-shaped piece, and between its two parallel sides, 

 are attached the ends of two flat springs, the latter 

 pressing from inside with their free ends against the two 

 parallel sides of the U-shaped piece provided with file 

 cuts. For pens that are not worn much it is sufficient to 

 let the points slide but a few times on the inner edge of 

 the angle-shaped piece, pressing it at the same time 

 against the file cuts. The nib is thus sharpened, and is 

 again fit for use. If, however, the pen has been used 

 very much it is passed several times between one side of 

 the U-shaped arm and the corresponding spring, and 

 then passed between the other side and the other spring. 

 The pen is then turned upside down and the operation 

 repeated. During the whole time the point of the pen 

 should touch the inner corner of the U-shaped piece. 



Induction Apparatus. — Mr. J. Swinburne has patented 

 an induction apparatus. The invention relates to induc- 

 tion apparatus for studying dynamo electrical machines. 

 When it is wanted to design a new type of dynamo it is 

 impossible to determine by calculation alone what a 

 machine made to a given design will do, and whether the 

 iron and copper and disposition of the machine are 

 as good as desired. According to this invention a sort of 

 model is made to scale. This consists of field magnets 

 made to scale,woundwith a known numberof turns ofwire, 

 and of a scale model of the iron of the armature. The 

 armature is also wound with wire, but it is unnecessary 

 to have an ordinary commutator, as two terminals are 

 arranged to lead the circuit in and out of the armature. 

 The armature need not be rotated, but is held in position 

 in the field, so that it can be moved round into an angular 

 position representing any desired lead of the brushes. 

 The induction through the armature corresponding to 

 any magnetising force due to any current round the field 

 is measured by a suitable induction balance. The 

 induction through any section of the armature is taken by 

 a pilot wire wound round that part. Similarly the 

 induction through any part of the magnetic circuit 

 can be measured. By passing a current through the 

 armature the conditions corresponding to the dynamo's 

 giving current can be investigated and the cross magnetisa- 

 tion and lead of brushes determined. A pilot coil is put 

 round the armature at a point corresponding to the 

 position of the brushes in the dynamo, and the induction 

 is then found for that section and for one or two 

 neighbouring sections, so that the lead of the brushes can 

 be determined. By this method the whole of the data 

 required can be determined, and the shape and disposition 

 of the iron can be altered by a few strokes of the file. 



TECHNICAL EDUCATION NOTES. 



Zurich Polytechnic School. — This school has long had 

 the reputation of being one of the best Continental estab- 

 lishments for the education of engineers, architects, and 

 chemists. A few years ago a new and very large chemical 

 laboratory was added, and now there is in course of erection 

 a still larger physical laboratory. Formerly the curriculum of 

 the mechanical engineers' school contained only a very mode- 

 rate amount of instruction in physics, and the head of the 

 mechanical school was invariably an engineer. Now, how- 

 ever, this policy has been entirely changed. The head of the 

 mechanical school is Professor Weber, a distinguished 

 scientist in physics, but not a mechanical engineer, and under 

 his auspices lessons in physical science occupy a very much 

 larger share of the instruction supplied to those who wish to 

 become mechanical engineers. The new laboratory will, 

 when completed, have cost about 3,2oo,ooofr., and will con- 

 tain thirty-eight rooms where physical investigations will be 

 carried on. Among these there will be four underground 

 rooms, situated so low that the temperature in them will only 

 vary by •2''C. between summer and winter. These are in- 

 tended for experiments which must be carried out at a 

 constant temperature. In the basement of the laboratory 

 will be installed various engines and dynamos, so that 

 students will be able to carry out experiments on a large 

 scale. No student will be allowed to compete for the diploma 

 of mechanical engineer unless he has worked for at least 

 forty days in the physical laboratory. Practical engineers 

 here consider that this new departure in the training of 

 mechanical engineers will not prove beneficial. They admit 

 that a somewhat larger share of instruction in physics is 

 desirable ; but they consider that under the new programme 

 the interests of practical engineering are likely to be injured 

 by an overdose of theoretical physics. — Industries. 



Exhibition of Works in Wood. — At the opening on 

 May 1 2th of this exhibition, Mr. S. W. Preston, the clerk of 

 the Carpenters' Company, read an address to the Lord 

 Mayor, tracing the circumstances which had led to the exhi- 

 bition, which had arisen out of the success of the similar 

 exhibition held in 1884. Technical education, the address 

 proceeded, was the important question of the day, and the 

 City and Guilds of London had now for some years been the 

 means of bringing that education within the reach of all, and 

 were gradually making it a necessity that every artisan worthy 

 of the name should avail himself of it. In 1885, 1886, and 

 18S7 the Carpenters' Company had free courses of lectures 

 given in tlieir hall on subjects connected with building. Last 

 October they opened a free technical library with all the best 

 works on carpentery and joinery, and in June next they pro- 

 posed to hold an examination. This examination would be 

 oral, and it was believed that those obtaining a certificate 

 would find it of great advantage in obtaining situations as 

 clerks of works. The Lord Mayor, in reply, congratulated 

 the Carpenters' and the Joiners' Companies on the success 

 they had achieved in their efforts to encourage the important 

 branches of trade with which their names were identified. 

 The examination which was to be held might have great 

 results, and he hoped that employers of labour would en- 

 courage what was being done by giving preference to those 

 artisans who had gained certificates. 



A Valuable Antiseptic. — Experiments made with 

 oxynaphthoic acid, which is now produced on a large 

 scale, show that one part of this substance kill as many 

 yeast fungi as five pares of salicylic acid. Stirred up in 

 cold water, this substance does not injure plants, 

 whilst it removes vegetable diseases, and destroys vermin 

 on fruit trees, especially the phylloxera. A number of 

 gold-fishes, cray-fish, and leeches, living in a tank con- 

 taining 880 gallons of water, were not injured by the 

 addition of 4^ oz. of oxynaphthoic acid, so that in such 

 proportions it may be safely used for the disinfection of 

 streams without any danger of injuring the fish. 



