August 22, 1902.] 



SCIENCE. 



291 



with fuming nitric acid; the action of an 

 alcoholic solution of mercuric chloride and 

 acetate of soda on same ; the action of sul- 

 phuric acid upon petrolenes 1605, 1606, 

 1607 ; bromine absorption and hydr.obromie 

 acid produced; the asphaltene complexes 

 obtained from samples 1605, 1606, 1607; 

 treatment of same with fuming nitric acid ; 

 bromine absorption and hydrobromic acid 

 produced; the chloroform soluble; 'soft 

 gum' and 'hard gum' — industrial products 

 obtained from Uvalde asphalt rock; proxi- 

 mate and ultimate composition of same; 

 synoptic table of the ultimate analyses; 

 table showing bromine absorption, hydro- 

 bromic acid liberated, and sulphur and ni- 

 trogen in the petrolene and asphaltene com- 

 plexes obtained from the asphalt rocks of 

 Texas; bromine absorption and sulphur 

 in asphalts, etc. ; heavy crude petroleum 

 from Watters Park, Texas; proximate 

 analysis of the residuum of sample 1601 ; 

 summary of results. 



On account of the large amount of ana- 

 lytical data presented a satisfactory ab- 

 stract of the paper is impracticable. 



Occurrence and Importance of Soluble 

 Manganese Salts in Soils: E. E. Ewell. 

 In the course of a qualitative examina- 

 tion of an acid soil which failed to grow 

 leguminous crops, it was discovered that the 

 soil contained a very considerable percent- 

 age of manganese compounds soluble in 

 water. An aqueous extract of the soil has 

 been found to contain about twice as much 

 manganese as calcium. It is believed that 

 this high proportion of manganese in the 

 soluble salts of this soil contributes very 

 largely to its sterility. The occurrence of 

 soluble manganese compounds in soils has 

 received so little attention in the past that 

 an extended investigation of the occurrence 

 of this element in soils has been undertaken 

 by the Bureau of Chemistry of the U. S. 

 Department of Agriculture. The investi- 



gation will include a study of the effects 

 of soluble manganese salts on plants, and 

 the agricultural importance of manganese 

 in soils. 



Black Rain in North Carolina: Chas. 

 Baskeeville and H. R. Wbllee. Ab- 

 stract published in the issue of Science 

 for August 8. 



A Modification of the Calorimetric Method 

 of Determining the Heat of Chemical 

 Reactions: Albert W. Smith and Ed- 

 ward J. HUMEL. 



The modification consists in keeping the 

 contents of the calorimeter during the re- 

 action whose change of heat is to be meas- 

 ured, at exactly the room temperature, by 

 the addition of water at the melting point 

 of ice. The method was proposed some 

 years ago by F. A. "Waterman for the de- 

 termination of the specific heat of metals. 

 It was found to be capable of yielding very 

 accurate results in determining the heating 

 value of fuels by the bomb-combustion 

 method, doing away wholly with two 

 troublesome sources of error in this deter- 

 mination, namely, the water equivalent of 

 the apparatus and the loss or gain of heat 

 by the apparatus from radiation. The 

 number of heat units is found from the 

 weight of ice water added and the room 

 temperature, both of which factors are 

 easily and accurately determinable. 



A Source of Error in the Chromic Acid 

 Method of Determining Carbon in Iron: 

 Albert "W. Smith and Burton B. Nied- 



ING. 



It was foimd that when the exit gases 

 from the apparatus, used for the determina- 

 tion of carbon in iron, during the oxidation 

 by chromic and sulphuric acids were passed 

 over pentoxide of iodine heated to 150°, 

 the presence of unoxidized carbon in the 

 form of carbon monoxide could always be 

 detected, usually in material quantities, 



