Junk 12, 1903.] 



SCIENCE. 



941 



Derivatives of Trichlorethylidene di-p-niiro- 

 phenamine: A. S. Wheeler and M. E. 

 Glenn. 



This body, on treatment with alcoholic 

 potash, gives a monohydroxy-derivative by 

 replacement of one chlorine; with sodium 

 methylate, a monomethoxy-compound ; with 

 bromine, a dibrom-derivative with bromine in 

 the rings; with zinc dust, a compound con- 

 taining no chlorine. 



Determination of Glycerine: A. S. Wheelee 



and W. E. Weller. 



Chaumeil's method in which iodic acid is 

 used was found to give high results. 



Mercurous Sulphide: Chas. Baskerville. 



This body was formed by the prolonged 

 action — through five years — of concentrated 

 sulphuric acid (99.65 per cent.) upon pure 

 mercury. 



Rtcent Worh on the Bare Earths in the 

 Chemical Laboratory of the University of 

 North Carolina: Chas. Baskerville. 

 An abridgment of his recent lecture before 

 the New York Section with two additions; 

 first, a new method for purifying neodidy- 

 mium (with Stevenson), and second, an elab- 

 oration of that portion touching radioactive 

 bodies and fluorescence. The paper was fully 

 illustrated with specimens and a few experi- 

 ments. 



Note on the Thermodynamical Calculation of 



the Latent Heat: J. E. Mills. 



Attention was called to the fact that when 

 the constants for Biot's formula were knovsra, 

 differentiation of this equation would give 

 SpjSt. Substitution in the ordinary thermo- 

 dynamical equation for calculating the latent 

 heat could then be directly effected, with a 

 great saving in the calculations involved. 



Molecular Attraction: J. E. Mills. 



If at any temperature the internal latent 

 heat of vaporization be divided by the differ- 

 ence of the cube roots of the densities of 

 liquid and vapor, the result should equal a 

 constant, according to a published theory of 

 molecular attraction {Jour. Phys. Chem., 

 April, 1902). It was shown that the latent 

 heats for ether, benzene and carbon tetra- 



chloride gave a good agreement with the 

 theory to within a few degrees of the critical 

 temperature. 



Some New or more or less Novel Forms of 

 Lahoratory Apparatus : J. M. Pickel. 



(a) An imusual form of siphon. 

 ( 6 ) A modified form of a previously described 

 filter-washer. 



(c) An automatic measurer and dispenser of 

 the acid used in Kjeldahl nitrogen determinations. 



(d) Same for the alkalies. 



(e) A stand for Kjeldahl digestion flasks. 



(f) A file for samples contained in bottles. 



(g) A desiccator for equalizing inside and out- 

 side air pressure. 



(A) An appliance for utilizing the incandescent 

 electric light as source of heat in fat extractions 

 with ether. 



(i) An asbestos furnace for gold assays. 



(/) An economical but efficient blast-lamp. 



(k) Spiral support for round-bottom flasks. 



An Efficient Asbestos or Graphite Muffle: 

 J. M. Pickel and C. B. Williams. 

 This mufSe has been used principally in 

 the determination of potash in fertilizers. It 

 is very efficient and has given satisfaction in 

 other respects. A description of it will soon 

 appear. 



After the completion of the program Dr. 

 Charles Baskerville tendered the members of 

 the section and their friends an informal 

 ' smoker ' at his residence. 



C. B. Williams, 



Secretary. 



the geological society of WASHINGTON. 



At the 144th meeting of the society, held in 

 assembly hall of the Cosmos Club, Wednesday 

 evening, May 6, 1903, the following program 

 was presented: 



Professor Lester F. Ward : ' Correlation of 

 the Potomac Formation in Maryland and 

 Virginia.' 



In this paper Professor Ward outlined the 

 present status of the Potomac formation, as 

 determined from numerous rich collections 

 made in recent years, chiefly by the Maryland 

 workers, and studied and reported upon by 

 Professor Fontaine. The position and extent 

 of the Potomac belt within Maryland and 



