I 6 8 Notes and Comments. [J. F. I.,
I M P R O V E D ELECTRIC INCANDESCENT L I G H T .
Nernst , a wel l .known German electrician, has pa t en t ed an i m p r o v e m e n in electrical glow l ights which consists in the use of a cyl inder of magnesia, or s imilar substance, which possesses the proper ty of be ing a non-conductor t of electricity when cold, aud of becoming conduct ive when hea ted to a h igh temperature. These cyl inders are provided wi th electr ical connect ions , and means - - such as a Bunsen bu r ne r - - a r e used to hea t t h e m to the conductive temperature , when the cur ren t alone will ma in ta in t hem in incandescence.
W.
N E W USES FOR GLASS.
Exper iments have lately been made wi th glass as a subst i tu te for metals for bearings. The .mos t suitable k inds were found to be bot t le and ordinary Window glass. The bear ings were cast in moulds, in two pieces. ' They gave the best results when m oun t ed in elastic supports. I t was found to be neces- sary t ha t the revolving par ts should be well ba lanced and the shafts accurately centered. The results are stated to have been t ha t the glass bear ings require less lubricat ion, have less friction, and in many cases are more advantageous t h a n meta l bearings, t hough in some cases they afford less securi ty than others.
I t is recorded in the F r e n c h journal , L'Eclairage Electrique, t ha t a t Mar- seilles, glass tubes are be ing used as underg round conduits for t e legraph wires and for carrying electr ic- l ight wires in factories, theatres, etc. W.
ASPHALT JOINTS FO R GLAZED S T O N E W A R E (TERRA-COTTA) PIPES.
In Germany, i t is said, asphal t jo in ts for terra-cotta pipes are now used in all the chief cities. The mel ted asphal t is poured around the socket end of the pipes when the two ends had been b rough t together . On tes t ing such joints by hydraul ic pressure, the pipes were found to give way before the joints showed any signs of leaking. W.
N I C K E L - S T E E L F O R M A R I N E B O I L E R S AND E N G I N E S .
The latest applicat ions of nickel-steel are in connect ion wi th marine boilers and engines. This alloy is found to be much superior to o ther kinds of steel for mar ine boiler plates on account of its greater resistance to the corrosive action of salt water. I t is also found to be excel lent ly adapted on account of its great toughness for parts of mar ine engines, especially for the hollow shafts used on the latest t ransat lant ic steamers. W.
COSMIC DUST IN HAIL.
Professor Karpinsky, a wel l -known Russian savant, recent ly made an inter- es t ing communicat ion to the St. Pe tersburg Academy on a fall of ha i l observed on April 3 o, 1897, by M. Czeruik, near Ivangorod, in Russian Poland.
The fol lowing account of the occurrence is t aken from London Nature :
