674 



SCIENCE. 



[N. S. Vol. IX. No. 228. 



diabase is 14 per cent, denser than melted 

 diabase, and 10 per cent, denser than the 

 glass produced by quick freezing of the 

 liquid. He gives no data, nor do Riicker 

 and Roberts- Austen, who have also experi- 

 mented on the thermodynamic properties 

 of melted basalt, give any data, as to the 

 latent heat evolved in the consolidation of 

 liquid lava into rock of basaltic quality. 

 Guessing it as three times the latent heat 

 of fusion of the diabase pitch-stone, I esti- 

 mate a million cubic centimeters of liquid 

 frozen per square centimeter per centimeter 

 per three years. This would diminish the 

 depth of the liquid at the rate of a million 

 centimeters per three years, or 40 kilo- 

 meters in twelve years. 



§ 25. Let us now consider in what manner 

 this diminution of depth of the lava ocean 

 must have proceeded, by the freezing of 

 portions of it ; all having been at tempera- 

 tures very little below the assumed 1420° 

 melting temperature of the bottom, when the 

 depth was 40 kilometers. The loss of heat 

 from the white-hot surface (temperatures 

 from 1420° to perhaps 1380° in different 

 parts) at our assumed rate of two (gramme- 

 water Centigrade) thermal units per sq. cm. 

 per sec. produces very rapid cooling of the 

 liquid within a few centimeters of the sur- 

 face (thermal capacity .36 per gramme, ac- 

 cording to Barns) and in consequence great 

 downward rushes of this cooled liquid, and 

 upwards of hot liquid, spreading out hori- 

 zontally in all directions when it reaches 

 the surface. When the sinking liquid gets 

 within perhaps 20 or 10 or 5 kilometers of 

 the bottom, its temperature* becomes the 

 freezing-point as raised by the increased 

 pressure; or, perhaps more correctly stated, 

 a temperature at which some of its ingre- 



* Tlie temperature of the sinking liquid rock rises in 

 virtue of the increasing pressure : but much less then 

 does the freezing point of the liquid or of some of its 

 ingredients. (See Kelvin, Math, and Phys. Papers, 

 Vol. III., pp. 69, 70.) 



dients crystallized out of it. Hence, begin 

 ning a few kilometers above the bottom, 

 we have a snow shower of solidified lava or 

 of crystalline flakes, or prisms, or granules 

 of feldspar, mica, hornblende, quartz, and 

 other ingredients : each little crystal gain- 

 ing mass and falling somewhat faster than 

 the descending liquid around it till it reaches 

 the bottom. This process goes on until, by 

 the heaping of granules and crystals on the 

 bottom, our lava ocean becomes silted up to 

 the surface. 



( To he concluded. ) 



THE POSTHOM* PHANTOM: A STUDY IN TEE 

 SPONTANEOUS ACTIVITY OF SHADO WS- 



At the April meeting of the Astral Camera 

 Club of Alcalde the veteran sciosophist and 

 former President of the Stanislaus Geolog- 

 ical Society, Mr. Abner Dean of Angels, 

 described his investigations of shadow-life, 

 as exemplified in the strange case of Peter 

 Schlemihl. 



It seems that this gentleman, late a resi- 

 dent of Kunersdorf, in Germany, on one 

 occasion was approached by a gray-haired 

 stranger who offered to purchase his shadow. 

 Schlemihl named a price, which was in- 

 stantly accepted. Thereupon the stranger 

 knelt upon the grass, rolled up the shadow, 

 folded it neatly and thrust it into his knap- 

 sack, at once disappearing down the road 

 between two hedges of roses, leaving Schle- 

 mihl himself absolutely shadowless. 



At first the poor man took the depriva- 

 tion lightly. But, as time went on, the 

 singularity of his position wore upon him, 

 the whispered words and doubtful glances 

 of his friends began to distress him, and 

 he fell into a condition of marked phys- 

 ical discomfort. He set out in search of 



* ' Posthumous Humanity:' A study of Phantoms, 

 by Adoljih D'Assier, Member of the Bordeaux Acad- 

 emy of Sciences. Translated and Annotated by Henry 

 S. Oloott; London, George Red way, York St., Covent 

 Garden. 



