MISCELLANY. 



38! 



here," says the author, " as excluding from 

 the possible causes of the light the luminos- 

 ity of gaseous matter, either spontaneous, 

 or due to electrical discharge. The sup- 

 position that the light is reflected from 

 masses of gas, or from globules of precipi- 

 tated vapor, is not to be entertained, since, 

 as ZoUner has shown, such globules in 

 otherwise empty space must evaporate 

 completely, and a gaseous mass would ex- 

 pand until its density became far too small 

 to exert any visible efifect upon the rays of 

 light." 



From this it follows that the light must 

 be reflected from matter in the solid state, 

 that is, from innumerable small bodies 

 (meteoroids) revolving about the sun in 

 orbits crowded together toward the ecliptic. 



The Great Lava-Flood of the West- 

 Prof. Joseph Le Conte, of the University 

 of California, visited, during the summer 

 of 1873, the central and eastern portions 

 of Oregon, a vast lava-covered region, and 

 published the results of his observations in 

 the American Journal of Science for March 

 and April, 1874. Using the word lava as 

 synonymous with eruptive rocks, he says 

 that between 200,000 and 300,000 square 

 miles of surface is one field of lava. It is 

 probably the most extraordinary lava-flood 

 in the world. Commencing in Middle Cah- 

 fornia as separate streams, in Northern Cali- 

 fornia it becomes a flood flowing over and 

 completely mantling the smaller inequali- 

 ties, and flowing around the greater ine- 

 qualities of surface ; while in Northern Ore- 

 gon and Washington it becomes an abso- 

 lutely universal flood, beneath which the 

 whole original face of the country, with its 

 hills and dales, mountains and valleys, lies 

 buried several thousand feet. It covers the 

 greater portion of Northern California and 

 Northwestern Nevada, nearly the whole of 

 Oregon, Washington, and Idaho, and runs 

 far into Montana on the east, and British 

 Columbia on the north. 



This enormous mass of matter evidently 

 arose through fissures, and flowed until the 

 streams or masses met, forming an almost 

 continuous sheet. The Cascade Range of 

 mountains seems to have been a source of 

 immense overflow. 



The area covered by this overflow can- 



not be less, says Prof. Le Conte, than 100,000 

 square miles, with an average thickness of 

 about 2,000 feet, but having a thickness in 

 some places of 3,700 feet. The statement, 

 which seems an extraordinary one, is sus- 

 tained by the extensive observations of 

 Prof Le Conte. The Columbia River cuts 

 through the Cascade Range in a gorge a 

 hundred miles in length, with perpendicular 

 cliffs. The cascades of the river are at the 

 axis of the range, and the cliffs here are 

 2,500 to 3,800 feet above the river-surface, 

 and are composed of lava, tier upon tier, 

 from top to b6ttom. Considering surface 

 erosion, 4,000 feet is regarded as a moder- 

 ate estimate for the original thickness of 

 the lava-flood at this place. 



But the entire thickness of the lava has 

 been cut through, and the surface revealed 

 on which the flood was originally formed. 

 Here, at the river's surface, underlying the 

 mountains of lava, are remains of ancient 

 forests, and evidences of interesting geolo- 

 gical changes. 



There occurs at the river's edge, and 

 about fifteen feet upward, a layer of coarse 

 conglomerate ; on this, a layer which ap- 

 pears to have been a dirt-bed, or old-ground 

 surface. On this surface were found two 

 silicified stumps, with their roots spread 

 out, one of which was two feet in diameter, 

 the roots reaching over an area twenty feet 

 in diameter. Trunks of other trees were 

 seen. Over this was a layer of stratified 

 sandstone, with beautiful impressions of 

 leaves of several kinds of forest -trees. 

 Upon this lies about 100 feet of conglomer- 

 ate, resembling drift, in the bottom of which 

 were found trunks and branches of oaks 

 and conifers. Upon the conglomerate the 

 lava lies in columnar masses to a height of 

 3,300 feet. 



The geological age of the wood and leaf- 

 bearing stratum is believed to be miocene, 

 or middle tertiary, and, if so, the lava-flood 

 began to occur during or after the miocene. 



Why Paints crack and peel. — A writer 

 in The Huh thinks that the cause of paint 

 cracking and peeling is to be found in the 

 water which is contained in linseed-oil, as 

 it comes from the hands of the manufact- 

 urer. He made the experiment of boiling 

 linseed-oil by the heat of steam, until all 



