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THE POPULAR SCIENCE MONTHLY. 



The Markings of Meteoric Stones. M. 

 Daubr^c, the eminent French geologist, in 

 his recently published work on " Synthetic 

 Studies in Experimental Geology," describes 

 some experiments that he has made for the 

 purpose of ascertaining the cause of the pe- 

 culiar appearance of the surface of meteoric 

 stones. These bodies are covered with a 

 blackish coating, which is sometimes dull 

 and sometimes brilliant, and indicates un- 

 mistakably that they have suffered modifi- 

 cations in passing through the atmosphere. 

 Their fracture presents a globular surface, 

 similar to the structure of terrestrial rocks, 

 showing that a strong cohesion has been 

 produced at the moment of their formation. 

 The outer surface is also covei'ed with round- 

 ed depressions forming little capsules. M. 

 Daubree had remarked that when a cannon 

 loaded with coarse-grained powder was fired 

 off, some grains, which were only partly 

 burned, would fall at the muzzle of the 

 piece. The hollowed surface of these grains 

 bore a striking resemblance to the forms 

 seen on the meteorites. He then performed 

 an experiment by taking a rectangular plate 

 of steel, rolling it up in such a way that it 

 should be fully enveloped by the gases from 

 the powder, putting it in a closed steel cham- 

 ber, with a quantity of powder, and firing off 

 the powder by means of the electric spark. 

 The duration of the deflagration was less 

 than half a second. The gases acquired a 

 tension of from one to two thousand atmos- 

 pheres, and a temperature estimated at about 

 3,600. The action, though of very short 

 duration, gave surprising results. The sur- 

 face of the plate was hollowed into irregular 

 furrows, which danonstrated the force of 

 the gaseous currents, and a powder of sul- 

 phurct of iron was found in the bottom of 

 the vessel. A half a second, then, was all 

 the time that was required to produce a par- 

 tial fusion of the steel, a considerable blow- 

 ing up by the gases, and such a chemical 

 action as the formation of a sulphuret of 

 iron. The experiment was repeated with 

 dynamite and other explosives, with identi- 

 cal results. From them, M. Daubree has 

 deduced the following interpretation of the 

 metecfric phenomena : the meteorites enter 

 the terrestrial atmosphere with an enormous 

 swiftness. The great pressure of air to 

 which they are subjected explains the incan- 



descence which takes place, and the superfi- 

 cial fusion of the mass. The part of a pro- 

 jectile of this kind which is at the moment 

 in front rams the air and compresses it ex- 

 ceedingly, and causes it to be agitated by 

 energetic gyratory movements. In whirl- 

 ing thus, under such pressure, the air tends 

 to screw and hollow out whatever it rubs 

 against, and this mechanical action is ac- 

 companied and reenforced by a chemical 

 action due to the combustible nature of the 

 meteoric rocks at these high temperatures. 

 These rocks contain enough particles of iron 

 in the native state, or as a sulphuret, to 

 largely favor combustion and disaggrega- 

 tion. Under these circumstances, the hollows 

 are produced, which appear on one side or 

 on all sides of the projectile, accordingly as 

 it has not or has a motion of rotation. M. 

 Daubree has given to these hollows the name 

 of piczoyhjptcs. 



Relation of Age and Marriage to Sui- 

 cide. It has been a mooted question wheth- 

 er the old or the young were more prone to 

 suicide. Statistics published by Dr. Bertil- 

 lon, in an article on marriage in the French 

 " Encyclopaedic Dictionary of the Medical 

 Sciences," prove that the propensity increas- 

 es with advancing age. They are reenforced 

 by statistics recently published in Sweden, 

 which lead to substantially the same conclu- 

 sion. The proportion of the number of sui- 

 cides of the more advanced ages to the whole 

 number of persons of corresponding ages ap- 

 pears to be less in Sweden than in France, 

 but aside from this the proportion increases 

 regularly in both countries from the age of 

 fifteen or twenty years to that of sixty years. 

 After about sixty years the tendency in both 

 countries appears to diminish. The propor- 

 tion of suicides among women is less at all 

 ages than among men, but increases with the 

 advance of years as with the men. The sta- 

 tistical work of Signor Morrelli, recently pub- 

 lished at Milan, lends additional support to 

 these views. Dr. Bertillon has also collect- 

 ed facts bearing on the effect of marriage 

 upon the tendency to suicide, from which he 

 has deduced the principles : 1. That widow- 

 ers and widows commit suicide more fre- 

 quently than married persons ; and, 2, that 

 the presence of children in the family 

 makes the probability of suicide more re- 



