1885-6.] on the Story of a Meteorite. 331 



The surfiice of so imperfect a conductor of lieat might be ignited, 

 while the interior of the mass remained intensely cold. We know 

 that imperfect conductors of heat, when heated to redness, and plunged 

 into cold water, so that they can be momentarily handled, will again 

 become nearly red hot on the surface, by heat derived from the 

 interior. Thus, specimens of lavas, which I collected in the crater of 

 Vesuvius, handled freely, and wrapped up in paper, frequently set 

 fire to the paper in a short time after they were so enveloj)ed. I 

 brought home many specimens which had browned and charred the 

 paper. 



It is also known to all assayers and chemists, that a crucible full 

 of melted flux, if cooled on the surface by plunging the crucible into 

 water, will soon become hot again on the surface, and that the interior 

 of the flux will remain red hot, while the surface of the crucible may 

 be held in the hand for a short time. 



Therefore, mutatis mutandis, there is no inherent improbability 

 that these masses of meteoric stone really would produce the sensation 

 of intense cold, if they were originally cold in the interior, and only 

 rapidly heated on the surface. If the facts are as alleged, this is the 

 first recorded recognition by the human senses of the cold of the 

 interplanetary regions. It would have been a curious and instructive 

 experiment, to have placed one of these stones, soon after it fell, in 

 water, when the formation of a crust of ice on the surface would have 

 visibly demonstrated the fact of intense cold ; and an estimate of the 

 degree of cold could also have been made, by similar means, ascer- 

 taining how much the temperature of a given quantity of water was 

 reduced by it, and computing the degrees of cold thereby. 



The weight of the fragment presented to the Society is 4J- ounces. 

 It is 2 J inches long, 1:^ inches wide, and 1 inch in average thickness. 



Its specific gravity is 3-456 at 68"^ Fahr., Barom. 29 • 9. Its struc- 

 ture is imperfectly granular, but not crystallised, and there are small 

 black specks of the size of a pin's head, and smaller, of malleable 

 meteoric iron, which is readily removed from the crushed stone by 

 the magnet. The colour of the mass is ash grey. A portion of the 

 surface is black and is scorified by fusion. 



Its hardness is not superior to that of olivine or massive chrysolite. 

 Chemical analysis shows that its composition is that of a ferruginous 

 olivine. 



One gramme of the stone, crushed in an agate mortar, and acted 

 on by a magnet, yielded 0*43 grm. of meteoric iron, which was 

 malleable. After the removal of this a qualitative analysis was made 

 of the residual powder. Another gramme was also taken, without 

 picking out the metallic iron, and was tested for chlorine and for 

 phosphoric acid. The results of the qualitative analysis were that 

 the stone contains silica, magnesia, a little alumina, oxide of iron and 

 nickel, a little tin, an alloy of iron and nickel, phosphoric acid, and a 

 trace of chlorine. 



These ingredients being determined, the plan for a quantitative 



