March 20, 1896.] 



SCIENCE. 



451 



elusion that the wave-length is affected little, 

 if any, by changes of temperature. 



The effect of pressure and amount of ma- 

 terial used, is discussed in the next article by 

 W. J. Humphreys and J. F. Mohler. Their re- 

 sults corroborate those of former investigators, 

 that an increase of the quantity of material in 

 the arc generally produces a slightly unsymmet- 

 rical broadening towards the red, and that in- 

 creased pressure causes a similar effect ; but 

 they find in addition that, upon the application 

 of pressure, a decided shift of the lines toward 

 the less refrangible portion of the spectrum 

 takes place, not due to broadening. 



The change in the case of any one element is 

 approximately proportional to the wave-length 

 and to the excess of pressure above one atmos- 

 phere. Whether the same law holds for very 

 low pressures could not be determined. The 

 shift for different metals at a pressure of four- 

 teen atmospheres often amounted to from five 

 to ten hundredths of an Angstrom unit. 



Theoretical considerations indicate that the 

 shift is inversely proportional to the absolute 

 temperature of the melting point. There is, 

 besides, a connection between the shifts and the 

 atomic weights. 



A third paper, by the authors of the first two, 

 contains a discussion of the effect of pressure 

 upon the reversing layer of the solar atmos- 

 phere. Assuming the atmosphere to be quies- 

 cent and the shifts to be due to change of pres- 

 sure only, they find the pressure of the revers- 

 ing layer to vary from two to seven atmospheres, 

 according to the weight of the element ob- 

 served. This seems to indicate that the upper 

 limits of the reversing layers of the different 

 elements are arranged somewhat in the order 

 of their atomic weights. 



THE AMERICAN GEOLOGIST, MARCH. 



Biographical Sketch of Charles Wachsmuth : By 

 C R. Keyes. Dr. Wachsmuth was known as 

 the foremost authority on fossil crinoids in 

 America, if not in the world. He spent most 

 of his life in Burlington, Iowa, where he first 

 acquired an interest in crinoids and where he 

 died on February 7, 1896, in his sixty-seventh 

 year. The sketch is accompanied by a portrait. 



The Structure of Certain Paleozoic Barnacles : 



By J. M. Clarke. The genus of fossil barnacles 

 called Lepidocoleus, which occurs in the lower 

 and upper Silurian and lower Devonian, is 

 shown to be a primitive and unmodified type 

 of iCirripede structure, consisting of but two 

 vertical ranges of plates, both series termina- 

 ting in a single plate which is axial and caudal. 

 The dorsal margin of the body is closed by the 

 interlocking of the plates, but the ventral mar- 

 gin is closed only by their apposition and was 

 dehiscent for the protrusion of the appendages. 



The Mineral Deposits of Eastern California: 

 By H. W. Fairbanks. The ore deposits dis- 

 cussed are chiefly those of gold and silver, the 

 occurrence of the former being treated in con- 

 siderable detail. The gold-bearing quartz veins 

 are considered as unquestionably of fissure 

 origin, and the contents of these veins bear no 

 particular relation to the mineral composition 

 of the country rock. 



Note on the Discovery of a Sessile Conularia — 

 Article I: By K. Ruedemann. The author 

 has found in the lowest part of the Utica shale 

 some specimens of Conularia gracilis Hall, to 

 which are attached peculiar cuneiform fossils, 

 and he has also found similar forms on two 

 specimens of the shell of Trochonema. Evi- 

 dence is presented to show that these peculiar 

 forms are the young of C. gracilis, as is also the 

 so-called plant, Sphenothallus angustifolius Hall. 

 These young individuals of Conularia were not 

 free but attached, and it is probable that the 

 adult forms were also sessile, although attached 

 adult specimens have not yet been found. 



A New Titanichthys : By E. W. Claypole. 

 The new form is much smaller than the other 

 species of the genus and is named Titanichthys 

 brevis. It was found by Dr. Clark, who has 

 discovered so many fossil fish in the Devonian 

 of Ohio. 



Thickness of the Paleozoic Bocks in the Missis- 

 sippi Basin: By C. R. Keyes. The estimate 

 made by various geologists of the Paleozoic 

 rocks of the Mississippi basin are given, and at- 

 tention is called to the fact that the estimates 

 of later years are considerably lower than the 

 others. A recent deep boring at Kansas City, 

 which is in the region of greatest thickness of the 

 Paleozoic, has passed through the entire (with 

 the exception of a part of the upper Coal meas- 



