MISCELLANY. 



631 



pearance of the great glaciers, wide sheets 

 of fresh water overspread some districts of 

 the State. The forest-bed (consisting of 

 roots, trunks, branches, and leaves of such 

 trees as sycamore, beech, hickory, and red 

 cedar) shows that by-and-by the fresh-wa- 

 ter basins were in some places filled up, and 

 the new soil covered with an abundant 

 forest-growth. After this came a period of 

 depression, when great deposits of gravel 

 and sand gathered over the surface of the 

 drowned laud, and large bowlders and er- 

 ratics were floated by ice from the north. 



These and other matters of interest and 

 importance will, no doubt, be fully treated 

 of in the final report, which is to consist of 

 four volumes, the first two being devoted to 

 the geology and paleontology of the State, 

 the third to its economic geology, and the 

 fourth to its agriculture, botany, and zoolo- 

 gy. A large collection of fossils has been 

 made, many species being new to science. 

 It is to be hoped that the good people of 

 Ohio will not grudge the money that will be 

 required for the adequate representation 

 and description of these remains, but that, 

 when published, the final report will be 

 found in every way as complete as those 

 admirable works which have been issued by 

 other States of the Union. Prof. Newberry 

 seems to have little doubt that it will be so, 

 for he thinks that the value and significance 

 of fossils are coming to be generally appre- 

 ciated. " There are, however," he says, 

 " yet some intelligent men, even editors and 

 members of Legislatures, who cherish the 

 notion that there is nothing which has any 

 value in this world but that thing which has 

 1 dollar in it, and that so plainly visible as 

 to be seen by them. Such men, to quote 

 the language of one of them, ' don't care a 

 row of pins for your clams and salamanders, 

 but want something practical.' " This 

 " practical " man must surely have been 

 related to that colonial official who is said 

 to have objected strongly to the expense of 

 " engraved portraits of extinct bugs and 

 beetles," as he irreverently styled certain 

 Silurian fossils. But the day of such wise- 

 acres has gone past, and it may be confi- 

 dently expected that Dr. Newberry and his 

 colleagues will have no difficulty in getting 

 the necessary funds voted for the comple- 

 tion of their important survey. Nature. 



MISCELLANY. 



Experiments on the Solar Spcstvam. 



Some experiments recently published by Dr. 

 John \V. Draper, of the New York Univer- 

 sity, on the heat of different portions of the 

 solar spectrum, will change, in several im- 

 portant particulars, the views hitherto held 

 on that subject. 



Until now, it has been supposed that the 

 heat of the spectrum is greatest below the red 

 region, and that it gradually declines as the 

 thermometer passes through the orange, yel- 

 low, green, blue, indigo, and violet, succes- 

 sively. 



Dr. Draper shows that, while this is true 

 as a matter of observation, the general con- 

 clusion drawn from it is altogether incorrect. 

 In the prismatic spectrum the red and less 

 refrangible colors are compressed together, 

 the violet and more refrangible are ex- 

 panded. This distortion is necessarily due 

 to the action of the prism itself. But, in the 

 difiractive spectrum, formed by lines drawn 

 with the point of a diamond on glass, the 

 arrangement of the colors is altogether dif- 

 ferent ; they are placed according to their 

 wave-lengths. 



Dr. Draper proves that, for the correct 

 solution of this problem of the distribution 

 of heat, the visible spectrum alone should be 

 employed, the ultra-red and ultra-violet in- 

 visible rays being removed. He next finds 

 the centre of the visible spectrum, proving 

 that it is a little beyond the sodium-line D. 

 He then, by the aid of a silver mirror, col- 

 lects all the less refrangible rays up to thi3 

 centre into one focus, and all the more re- 

 frangible rays from this centre into another 

 focus, and measures the heat of each. On 

 the received view, the former of these foci 

 should contain nearly all the heat, the latter 

 little or none. In several hundred experi- 

 ments in which exact measures have been 

 made, it turn3 out that the heat is the 

 same in both. 



From this, some very remarkable results 

 follow. Among them we may mention, that 

 all the rays of the spectrum, irrespective of 

 their color or wave-length, have equal heat- 

 ing-power ; and that, in fact, the heat 

 manifested in any part of the spectrum ia 

 due to the stoppage of the motion Of the 



