SCIENTIFIC NEW^S. 



[May iS, iS88. 



kindles wet thatched roofs, and why it strikes trees, often 

 stripping the bark without shattering them ; why the 

 neiglibourhood of waterfalls, of overflows from cisterns, 

 and even of brooks and streams is dangerous. 



Earthquakes. — A severe shock was felt on the west 

 coast of Norway on April 2nd. On April i8th a shock 

 lasting for about two minutes was felt in the South of 

 Sweden. According to the Chilian Times of March loth, 

 a series of earthquakes, commencing at i p.m., (were ex- 

 perienced at Caracoles on February 24th. The shocks 

 were also felt at Calama and Sierra Gorda. A shock of 

 earthquake was experienced at Valparaiso at 6.35 a.m. 

 on March loth. A smart shock of earthquake, followed 

 by a loud subterranean roar, was experienced at Quillota 

 on the 6th at 6.30 a.m. A severe earthquake shock was 

 experienced in Ovalle on the 5th at 5.19 a.m. The 

 shock was also felt in Serena, where it lasted 40 seconds. 

 The direction of the wave was north to south. The 

 shock was also felt at Illapel. 



A River Phenomenon. — The river Mersey in the 

 vicinity of Warrington Bridge has presented a startling 

 appearance on several evenings recently. Bubbles of 

 spontaneously inflammable gas have been rising in 

 patches on its surface, bursting into brilliant flame on 

 contact with the air, with an effect so weird as to lead to 

 much speculation and wonderment amongst the 

 numerous spectators who have gathered to witness the 

 phenomenon. At times the flashes of light have cor- 

 uscated on the river in large tracts, emitting a bright 

 light accompanied by a noise like miniature artillery. 

 The cause is variously assigned to some experiments 

 which are being made for the purpose of devising a 

 signal light for use at sea, or the natural formation in the 

 muddy bed of the river of phosphuretted hydrogen, 

 which bursts into flame on contact with air. 



Electric Fire Alarm. — According to the Electrical 

 Engineer, M. Plan has devised a very simple apparatus 

 for indicating a rise of temperature in any portion of a 

 building. The essential part is a glass globe, the neck 

 of which is closed by a membrane which, by the expan- 

 tion of the contained air, is made to close the circuit of 

 a battery and bell. The apparatus is regulated by means 

 of a screw, carrying one of the platinum points being 

 brought into contact by the inflation of the membrane, 

 while the other platinum point attached to a spring in close 

 proximity to the membrane. In order to render the in- 

 strument independent of barometric and ordinary tem- 

 perature variations, it has been found advisable to 

 establish a communication, by means of a minute orifice, 

 between the enclosed air and the surrounding atmosphere. 

 By means of this device only sudden variations of 

 pressure, such as would be due to a current of heated 

 air arising from combustion, are indicated. The appara- 

 tus should be placed at a considerable altitude above the 

 floor; and we think that the objection of fragility. might 

 require to be obviated by the use of a globe or other 

 vessel of copper, in lieu of one of glass. 



Obituary. — It is with regret that we have to record 

 that Professor Segmund Wroblewski, of the University of 

 Cracow, has succumbed to the effects of the severe burns 

 which he met with while working in his laboratory. Dr. 

 Wroblewski has contributed several important papers to 



the scientific press upon his work on the liquefaction of 

 the so-called permanent gases. By much labour and 

 perseverance he has succeeded in completing the work 

 which the French and Swiss chemists MM. Pictet and 

 Cailletet started, and some three years ago his efforts 

 were crowned with a successful experiment, in which he 

 obtained atmospheric air in a liquid form. Besides 

 liquefying oxygen, nitrogen, and hydrogen gases, and 

 determining the temperatures at which these elements 

 when in a liquid state boil, Dr. Wroblewski was the 

 first to freeze carbon bisulphide and alcohol into a solid 

 condition. Before his work in this direction all attempts 

 at the solidification of these two Hquids had failed, but 

 with the appliances which had so successfully aided him 

 in his researches with the gases we have mentioned he 

 succeeded in obtaining sohd alcohol, and thus confirmed 

 our theories in respect of this liquid. Professor 

 Wroblewski was born in the year 1848, and studied at 

 St. Petersburg and Strasburg. He was appointed to the 

 chair of experimental physics at Cracow in 1882, and his 

 chief work has been accomplished within the last few 

 years. The fatal termination to his accident has caused 

 the loss of a careful investigator in a branch of physics 

 which is of more than usual interest. 



Petroleum Lamp Explosions. — Herr D. Fock, in a 

 lecture delivered before the Prussian Industrial Society, 

 in Berlin, gave an account of some experiments made by 

 the German Standards Commission. If a petroleum lamp- 

 be not full, the upper part of the reservoir contains air 

 charged with petroleum vapour, the proportion of which, 

 depends on the character of the oil and upon its tempera- 

 ture. Let a flame enter, and there is ignition, which, in 

 a closed reservoir, may produce a pressure of fourteen 

 atmospheres, or 210 lbs. to the square inch; but the 

 force of this explosion depends upon the ratio between 

 the air and the petroleum vapour present ; the most 

 violent explosion is produced by a mixture of forty-three- 

 air, and one petroleum-vapour ; if the mixture be poorer 

 or richer than this, the combustion is slower and the 

 action less violent. The temperature at which petroleum 

 will give off so much vapour as to flash, is the " flash- 

 point ; " some 8° C. above this is the temperature at 

 which the most violent gaseous mixture explosion is 

 probable ; and some \Z C. still higher up the scale is the 

 " kindling point," at which the petroleum itself will 

 ignite when flashed, but at which there is no danger of 

 explosion in a closed reservoir, the proportion of vapour 

 present being too great. Fock points out that actual 

 explosions of the oil reservoir are almost unknown ; he 

 has tried to produce explosions in some 1,500 lamps, and 

 only succeeded once,for even cracked ones do not explode; 

 the internal pressure is, under normal circumstances, 

 relieved through the wick holder. The result of the 

 investigations of the Commission is that the risk of 

 explosion proper is very small. The explanation of the 

 numerous fatal accidents appears to be rather that in a 

 warm room, or from the flame heating the lamp itself, the 

 petroleum has reached its " kindling point," which 

 lies in common commercial petroleum at about 2,'^° C.,. 

 or 9i'4° F., the copious vapour produced comes up the- 

 wick tube, mixes with air, and burns in the wick ; the 

 wick holder is heated, something, cracks ; and the petro- 

 leum bursts into flame. To avoid this, glass reservoirs- 

 should be strictly tabooed ; they should be of .metal or 

 some material which would n-ot be likely to crack when, 

 heated in the above way. 



