854 



SCIENCE. 



[N. S. Vol. XXIV. No. 626. 



other families, so that the South American 

 relationship of the Jamaica flora is more inti- 

 mate than that of Cuba, Hayti or Porto Eico, 

 and it is suspected that this may be an indi- 

 cation of a former land connection between 

 Jamaica and the continent to the west or 

 southwest. Dr. Britton's paper included a 

 complete enumeration of the species now 

 known, together with diagnostic keys for their 

 •determination and as much of their synonymy 

 as relates to Jamaican records. No unde- 

 ■scribed species were found, but the collections 

 made by recent explorers added a number to 

 those recorded by Mr. Clarke in his mono- 

 graph of the West Indian Cyperacese, pub- 

 lished in the second volume of Professor 

 Urban's ' Symbolse Antillanse.' 



Exhibition of Photomicrographs of North 

 American Woods: Dr. C. Stuart Gagee. 

 Numerous specimens were shown from a 

 collection of photomicrographs of cross-sec- 

 tions of North American woods, recently ac- 

 quired by the garden from Mr. James A. 

 Weale, of the firm of Williams, Weale & Co., 

 of Liverpool, England. These photomicro- 

 graphs are all enlarged ten diameters, thus 

 facilitating comparison. They are of very 

 superior quality, so that many finer elements 

 of the histology of the various woods can be 

 demonstrated under a lens with nearly as 

 great satisfaction as from the original sec- 

 tions. They possess the advantage of being 

 less fragile than the sections themselves, and 

 of serving better than they for purposes of 

 demonstration before classes and otherwise. 

 The collection contains representations of 

 practically all North American species. 



By way of comparison, specimens were 

 shown of Hough's 'American Woods' and of 

 Nordlinger's ' Holzquerschnitte.' 



C. Stuart Gager, 



Secretary. 



THE AMERICAN CHEMICAL SOCIETY. NEW YORK 

 SECTION. 



The second regular meeting of the session 

 of 1906-7 was held at the Chemists' Club, 

 108 W. 55th St., on December 7. The present 

 •councilors, Messrs. Leo Baelkeland, F. D. 



Dodge, T. J. Parker, W. J. Schieffelin and 

 Hugo Schweitzer, were reelected. 



The following papers were presented: 



A Necessary Modification of Volhard's Method 

 for the Determination of Chlorides: M. A. 

 EosANOPF and Arthur E. Hill. 

 The authors set forth the advantages of 

 filtering off the insoluble silver chloride 

 formed in the reaction demonstrating by ex- 

 periment the indefinite end point obtained 

 when this is not done. The subject awakened 

 considerable discussion among several mem- 

 bers present who had made many determina- 

 tions by Volhard's method and who questioned 

 the advantage of the modification. 



The Color Change in Chromic Chloride Solu- 

 tions: Arthur B. Lamb. 

 The speaker showed, by an experiment on 

 the lecture table, that the change in color 

 from green to violet of a solution of green 

 chromium chloride was accelerated by adding 

 a salt of a weak acid like acetic and greatly 

 retarded by adding a strong acid as hydro- 

 chloric. The application of the principles of 

 the ionic theory to this and related transfor- 

 mations was dealt with at some length. At- 

 tention was called to the explanation, afforded 

 by this investigation, of some results by Wein- 

 land and Koch, showing the varying amount 

 of chlorine precipitated from solutions of 

 green chromium chloride by different silver 

 salts. 



Some New Double Phosphates: L. J. Cohen. 

 The properties of a number of salts of phos- 

 phoric acid were described and their analyses 

 compared with the theoretical. 

 Note on a Strange Case of Poisoning : M. T. 



BOGERT. 



A case of poisoning in the distillation of 

 certain bromine compounds, where deep de- 

 struction of tissue, with no apparent external 

 injury, was caused by very brief contact of the 

 hand with the vapors. Professor Bogert fur- 

 ther spoke of the desirability of calling atten- 

 tion to injuries received in handling corrosive 

 materials in order that suitable precautions 

 might be taken by future investigators. 



C. M. Joyce, 

 Secretary. 



