572 



THE POPULAR SCIENCE MONTHLY. 



powder lost all its sulphur, but did not take 

 fire. With a lamp inclosed in a bell glass 

 the three explosive substances were decom- 

 posed in twenty minutes. Water, with 

 which the interval was filled, came to the 

 boiling point in fifteen minutes. It was ob- 

 served even when the beginning of an igni- 

 tion of the explosives was determined, the 

 flame was not sure to be propagated, unless 

 the substance had been previously warmed. 

 On the other hand, a derivation of weak re- 

 sistance, produced between the two conduct- 

 ors of a lamp, determines a strong flame, ca- 

 pable of igniting all combustible substances. 

 A lamp may be broken by a shock, by 

 overheating, or by some unknown cause. If 

 only a crack is formed, the air getting with- 

 in causes the filament of incandescent carbon 

 to burn up in a very short time. If the lamp 

 bursts or has a hole made in it, the danger is 

 greater, and may cause the ignition of ex- 

 plosive gases, but not of fulmicotton or dry 

 powder. It is not safe, therefore, to con- 

 clude that an accident is absolutely impos- 

 sible. 



The Whirlpools of Charybdis and Scylla. 



— Charybdis and Scylla, the whirlpools of 

 which much was fabled in classical antiquity, 

 are situated in the strait of Messina, between 

 Sicily and Italian Apulia. Although they 

 were a great terror to ancient navigators, 

 they are in reality rather small affairs, and 

 it is difficult to determine their exact posi- 

 tions. The whirlpool of Scylla is situated at 

 the foot of the cliffs on which is the little 

 city of that name, which are hollowed out 

 into caverns. The circulation of the waves 

 in these grottoes produces, in times of heavy 

 seas, a sound like the barking of a dog. 

 Charybdis is near the port of Messina, nine 

 marine miles from Scylla. Although it was 

 reported unfathomable, it is, according to 

 Spallanzani's measurements, not more than 

 five hundred feet deep, and is therefore far 

 from being the deepest spot in the Mediter- 

 ranean. It is difficult to comprehend why 

 the ancients should have had such a terror 

 of sailing between these two eddies so far 

 apart, but the task of explaining the riddle 

 has been undertaken by the engineer, M. 

 Keller. Observations made by him at Mes- 

 sina show that the currents of the strait de- 

 pend, first, on the tide, and, secondly, on the 



wind. The currents are very strong, because 

 the tide is low in the Ionian Sea when it is 

 high in the Tyrrhenian Sea, and vice versa. 

 Hence, also, the formation of whirlpools at 

 different points in the strait. These whirl- 

 pools are energetic in proportion to the 

 strength of the current, and when at their 

 strongest may offer a serious danger to navi- 

 gation. At the syzygies, with the wind 

 from the southeast, the waters tumble from 

 the Ionian Sea into the strait and form 

 whirlpools north of the port of Messina; 

 they are likewise formed near Faro, where 

 ships at anchor are sometimes carried out to 

 sea and borne by the current upon the rocks 

 of Calabria, toward the point of Pezzo, a 

 little farther away than Scylla. We may 

 therefore suppose that the ancients meant by 

 Charybdis these casual whirlpools near the 

 port of Messina, and by Scylla those of 

 Point Pezzo. Between these two points the 

 currents are extremely rapid and strong and 

 variable besides. Under such circumstances 

 an inexperienced sailor might therefore have 

 difficulty in passing the strait of Messina 

 without falling from Charybdis into Scylla. 

 The danger is really serious for sailing ves- 

 sels, which were the best the ancients knew of. 



Consumption at Davos Platz. — A case is 

 recorded by Dr. A. T. T. Wise, of Davos 

 Platz, Switzerland, of a consumptive mani- 

 festing serious symptoms ordered to that 

 place for the mountain air, who began to re- 

 gain lost ground in two weeks after his 

 arrival, near the end of October, 1891. Pro- 

 gression toward recovery, with gradual ex- 

 pansion of the chest and gain in weight, was 

 uninterrupted till February, 1892, when the 

 physician's examination showed improvement 

 near to recovery in every affected part. In 

 October, 1892, the patient, having gained 

 twenty-eight pounds in Davos, had resumed 

 his practice of medicine, was in robust health, 

 and presented no sign of disease except a 

 faint, hardly perceptible expiratory harsh- 

 ness over the left apex. The climatic ad- 

 vantages at high altitudes in pulmonary dis- 

 ease, as summarized by Dr. Wise, are : Dry- 

 ness of the air and its comparative freedom 

 from micro-organisms and atmospheric dust, 

 entailing a lessened liability to catarrh and 

 irritation of the bronchial tract and drying 

 the lungs ; profusion of sunlight ; with the 



