December 14, 1883.] 



SCIENCE. 



781 



of the best Cuban woods, with a view to exhibiting 

 the resouicos of his country in this direction, and to 

 the opening of our markets to his native limber. The 

 researcli was made in the meclianical laboratory of 

 the department of engineering of tlie Stevens insti- 

 tute of technology, and included tlie determination 

 of moduli of resistance in tension, torsion, and com- 

 pression, as well as for transverse loading. The woods 

 are specified by their Cuban and by their botanical 

 names, and can thus be identified. The first part of 

 the work is now published ; and the moduli of elas- 

 ticity found for forty woods of sixteen distiiict species 

 are given, together with a full description of the 

 apparatus, and the methods of test. These moduli 

 are all high, and run very uniformly, usually above 

 two millions. But one (Caoba) falls under a rail- 

 lion and a half. The stiffest woods are the Dagame 

 (Colycophyllum candidissimum) and the Jiqui Comun 

 (Bumelia nigra), which have a modulus of two mil- 

 lions and a half. 



The woods described are nearly all hard, strong, 

 heavy, highly colored, taking a handsome finish, and 

 excellent for constructive purposes. Some of them 

 are not liable either to decay, or to injury by insects. 

 They seem quite likely, should they become known 

 through Mr. Estrada's work, to jirove exceedingly 

 valuable additions to the stock of available woods for 

 the American market ; and their introduction is likely 

 to afford a valuable commerce, if it is properly encour- 

 aged by our own consular department and the Cuban 

 officials. A full account of this part of the investi- 

 gation is given in Van Xostrand' s majazine for No- 

 vember. 



— The Johns Hopkins university circular for No- 

 vember announces the resignation of Professor Syl- 

 vester from the chair of mathematics, and his early 

 return to Europe. His loss to this country will be 

 keenly felt by our mathematicians, for his presence 

 and activity have given mathematical studies a re- 

 markable stimulus in this country. We notice, in tlie 

 December number of the American journal of maili- 

 emntics, so long conducted by Professor Sylvester, 

 the name of Dr. Craig given as assistant editor, which 

 we trust indicates that it will be continued by the lat- 

 ter after Profe«sor Sylvester's departure. The Johns 

 Hopkins university has recognized the value of Pro- 

 fessor Sylvester's services by electing him professor 

 emeritus, and by passing resolutions in which the 

 board of trustees "cordially extend to him its hearty 

 thanks for the invaluable services which he has ren- 

 ilered to the university, and also its profound sense 

 of the great ability, the conscientious fidelity aiul 

 untiring energy, with which he has discliarged the 

 arduous duties of his chair, thereby elevating the sci- 

 ence of mathematics to its proper plane, not only in 

 this institution, but in this country." 



The circular also announces the acceptance by 

 Dr. Paul Haupt, professor of Assyriology in the Uni- 

 versity of Goltingen, of a call to the Jidins Hopkins 

 university as professor of the Shemitic languages. 

 Dr. Hanpt has alrctdy commenced his work, and 

 has classes organized in Hebrew, Arabic, Assyrian, 

 Ethiopic, and Sumero-Accadian. 



— Killingworth Hedges described to the British as 

 sociation the fire risks of electric lighting, and is thus 

 reported in \a(ure. There is a great difference be- 

 tween the electric currents which have been in con- 

 stant use for telegraphic purposes and those which 

 are to be supplied by the undertakers under the 

 Electric-lighting act. The 'latter can be .«aid to be 

 free from danger only when the heat generated by 

 the current is utilized in its right place, and not devel- 

 oped in the conductors or wires which lead the elec- 

 tricity to the incandescent lamps. The Fire-risk 

 committee have already issued rules for guidance of 

 users of electric light. These can hardly be said to 

 embrace all the salient points of the new subject, 

 which can only be arrived at after years of practical 

 work. The necessity of proper regulations has al- 

 ready been recognized by the insurance-offices, both 

 in the United States and Germany ; and some of their 

 special rules are given in this paper. The conductors 

 must be properly proportioned for the current they 

 have to carry. Whatever resistance there is in the 

 conductor will cause a corresponding development of 

 heat, which will vary with the amount of electricity 

 passing, and inversely as tlie sectional area. As the 

 temperature in Dr. Matthiessen's experiments upon 

 the subject was not increased over 10o° C, the author 

 has made some further experiments, heating the wires 

 by the electric current from a secondary battery to 

 within a few degrees of their melting-point. Various 

 materials were tried ; the wires and foils having such 

 sectional area, and being so arranged, that, on the 

 current being increased by twenty percent, they were 

 immediately fused. The total length of each experi- 

 ment was twenty-four hours, during whiih lime the 

 current passing through varied slightly/ The results 

 of the experiments were given. 



— Mr. Joseph Thacher Clarke is giving a course 

 of three lectures on classical archeology before the 

 Johns Hopkins university, in one of wliich the re- 

 cent work at Assos, under his direction, will receive 

 special attention. 



— On Nov. 13 the Arlberg tunnel, the third largest 

 not only in Europe but in the world, was opened. 

 It was not exactly the formal opening which took 

 pl.ace Nov. 13 (this was celebrated Nov. 20), but the 

 sounding-rod (three metres long) of the powerful 

 boring-machine penetrated from the west side to the 

 east gallery. A mass of rock sixty centimetres thick 

 still separated the two galleries. One gallery was 

 driven from St. Anton, on the Tyrolese side, and the 

 other gallery from Langen in Vcirarlberg. Both gal- 

 leries sloped upward into the mountain; the Tyro- 

 lese rising two feet in a thousand, the sleeper Vorarl- 

 herg fifteen feet in a thousand. When the Tyrolese 

 section had penetrated 4,102 metres, it was contin- 

 ued downwards at lln' grade of the eastern end, the 

 point of inter>ectiou lying nearer the west than the 

 east mouth of the tunnel. As with the St. Gothaid 

 tunnel, there was but one mistake in the measure- 

 ment, lh<" length of the tunnel being three metres 

 less than was computed. 



The construction of the tunnel (10,263 metres long 

 was begun June 22, 1880, by baud, and Nov. 13 of 



