208 



SCIUNCJE. 



[Vol. IX., No. 213 



turbance, while those of Etna and at Catania were 

 much agitated. The steamer Guadeloupe felt two 

 shocks in latitude 43° 45' N. and longitude 5° 39' 

 E. at 6 A.M., and a third one at 8 A.M. At Cannes 

 and Antibes the sea fell three feet at the moment 

 of the chief shock, and then rose six feet. The 

 seismoscope at Washington was disturbed at 7.33 

 A.M. On Feb. 24, slight shocks occurred at 

 Mentone and at Digne (Departement des Basses 

 Alpes), and on the following day at 1.53 a.m. a 

 shock was reported from Nice, and at 2 and 4 a.m. 

 from Cannes. 



This earthquake occurred on the large fault on 

 the south - western side of the Apennines. A 

 glance at the map shows the difference between 

 the declivities of the Apennines. • North of Genoa 

 the Molasse hills gradually rise from the plains 

 of Piedmont, forming a continuous curve, which 

 may be observed from here to the Bay of Taranto. 

 Inside of this continuous belt we lind limestone, 

 forming the Abruzzo, Gran Sasso, and the Basili- 

 cata. This line is interrupted in Tuscany. Still 

 farther inside, on the west coast, and partly sub- 

 merged in the Tyrrhenian sea, we find the sepa- 

 rated dibris of the ancient crystalline rocks. Here 

 is the great fault between the sunken tract now 

 occupied by the Ligurian and Tyrrhenian seas and 

 the mountains. It is marked by the long lines of 

 volcanoes and countries of frequent seismical dis- 

 turbances. The east side of the Apennines is regu- 

 larly folded : the west side is torn, and a seat of vol- 

 canic and seismic action. The folded side is convex 

 and continuous : the opposite one is broken by faults 

 and sunken tracts. Inside of the Apennines there 

 are a great number of sunken tracts arranged on 

 a long line, the curved limits of which cut far 

 into the range of mountains : the Gulf of Genoa, 

 Salerno, Naples, and the bay around the Lipari 

 Islands are the centres of regions of this kind. The 

 movements of the strata along these faults give 

 rise to the numerous violent earthquakes of 

 western Italy. 



LONDON LETTER. 



The unsavory subject of the disposal of London 

 sewage continues to attract much attention, and 

 to create considerable interest. On three succes- 

 sive evenings the large theatre of the Institute of 

 civil engineers has been crowded to excess to hear 

 the discussion on papers by Messrs. Dibdin and 

 Crimp on sewage-sludge and its disposal. The 

 most telling speech was that of Dr. MeymoltTidy, 

 who, ia a most incisive manner, delivei-ed a heavy 

 indictment against the Metropolitan board of 

 works, on the ground, that, when forced by public 

 opinion to do something to remedy the nuisance 



in the Thames, they summoned to their aid the 

 very chemists vs^ho had previously given evidence 

 before a royal commission to the effect that there 

 was no sewage nuisance in the river ! He ridi- 

 culed unsparingly the treatment by lime and fer- 

 rous oxide, and by sodium manganate, which had 

 been adopted by the board, and also Mr. Dibdin's 

 view that the ferious oxide acted as a carrier of 

 oxygen between the air and the sewage in w^hich 

 it was suspended. The idea that sewage could be 

 ' made to pay ' had done more than any thing else 

 to restrict advances in the mode of dealing with 

 it : such processes were like those for extracting 

 silver out of sea-water. On another occasion the 

 advocates of irrigation and sewage farms had 

 their say at the Society of arts, where Dr. Alfred 

 Carpenter gave his experiences of the Croydon 

 sewage-farm, near London, which were very 

 favorable. Such an opinion has especial value, as 

 the author is well known as a distinguished sani- 

 tarian and medical ofiBcer of health. The local 

 conditions for successful sewage-irrigation are not 

 easily obtainable. There are, however, many 

 places near American cities, within the knowledge 

 of the present writer, where sewage-irrigation 

 might be applied with the greatest advantage. 



Another subject much before the scientific pub- 

 lic at present is the employment of gas for lighting 

 and heating. Mr. Colnaghi has lighted a small 

 picture-gallery most efficiently by the gaslight 

 system of Dr. von Wolsbach of Vienna. The 

 figures given are an average consumption in each 

 burner of two feet per hour, at a pressure of nine- 

 tenths of an inch, and an average illuminating- 

 power of seventeen candles, or eight and a half 

 candles per cubic foot of gas consumed. Within 

 an ordinary atmospheric or Bunsen flame, is placed 

 a mantle or hood of cotton net or webbing which 

 has been previously steeped in a solution of oxides 

 of zirconium and lanthanium. Mr. William Sugg, 

 the well-known gas-engineer, lately gave a most 

 successful gas-cooking demonstration, in which 

 the non-luminous flame is abandoned in favor of 

 the radiant heat from a luminous flame in a well- 

 ventilated chamber. The gas supply is regulated 

 by a govejnor, and the results can be predicted to 

 a nicety. The loss in roasting a joint is reduced 

 from twenty-five per cent to eight or twelve. 

 Neither the food nor the vessels containing it are 

 touched by the flame : hence unpleasant flavors 

 are avoided, and the whole apparatus, which is 

 adaptable to many different culinary operations, 

 has the merit of great simplicity. A very striking 

 lecture, well illustrated, was recently given to the 

 Manchester technical school, on ' Some curious 

 flames,' by another gas-engineer, Mr. Thomas 

 Fletcher. He strongly insisted, that, in the ab- 



