January 2, 1920] 



SCIENCE 



19 



The curves plotted from the results of the 

 determinations made on acid soils and on the 

 decomposition products of the soil-forming 

 minerals are similar to the one described 

 above, while those made on neutral or alkaline 

 soils are similar to lines he and cd of that 

 curve. This apparently indicates that there 

 are some dissociated acids or acid salts pres- 

 ent in the solutions of acid soils, and of the 

 decomposition products; and that with all of 

 the materials some of the calcium hydroxide 

 is entirely removed from the field of action. 

 These statements are interesting, especially 

 when compared with the conclusions drawn in 

 regard to soil acidity from results obtained by 

 the freezing^ point method. The conclusions 



Pig. 1. 



by that method are contrary to the former of 

 the above statements, but agree with the latter. 

 Some other interesting facts concerning 

 these curves are that where they first reach 

 the neutral line, they show a lime requirement 

 as determined by the so-called Jones^ method; 

 and that where they leave the neutral line, 

 they may indicate what Sharps and Hoagland 

 term "potential acidity" or what Bouyoucos* 

 terms " maximum lime requirement." It is 

 also interesting to note that the curves vary 

 somewhat when bases other than calcium hy- 

 droxide are added to soils. Barium hydroxide 

 gives rise to curves similar to calcium hy- 

 droxide, while sodium and ammonium hydrox- 

 ides gives curves represented by lines ah and 

 cd in the above figure. 



1 Mich. Agric. Col. Exp. Sta. Technical Bui., 

 No. 27. 



2 Jour. A. 0. A. C, Vol. I., p. 43. 



3 Jour. Agric. BesearoJi, Vol. VII., p. 123. 



< Mich. Agric. Col. Exp. Sta. Technical Bui. No. 

 27, p. 37 



This work is being continued with the hope 

 that within a short time sufficient data will 

 be obtained to warrant a more complete dis- 

 cussion of the subject. O. B. Winter 



Michigan Agwcultukal College, 

 ExPEEiMENT Station 



ALABAMA MEETING OF THE ASSOCIA- 

 TION OF AMERICAN STATE 

 GEOLOGISTS 



One of the most successful and profitable annual 

 field meetings of the Association of American 

 State Geologists was held in Alabama, September 

 1 to 6, 1919, on invitation and under the able 

 guidance of the state geologist, Dr. Eugene A. 

 Smith. Headquarters were at the Tutwiler Hotel, 

 Birmingham. 



An instructive printed guide of 14 pages briefly 

 summarizing the essential geologic features to be 

 observed at each place visited in the state was 

 prepared by Dr. Smith and associates. As orig- 

 inally planned, the program called for a division 

 of the party into two sections (Highland and 

 Coastal Plain), to be together only on the first 

 and last days. This .plan was later modified to 

 exclude the Coastal Plain section, but was closely 

 adhered to for the Highland section, which closed 

 with a visit to the University of Alabama, so long 

 and well known to geologists as the home of the 

 distinguished host, Dr. Smith. 



Much of the Highland region of the state, long 

 known for its varied and complex geology, was 

 covered by excursions, and many of the interesting 

 features of physiography, structure, stratigraphy 

 and economic geology, were reviewed. Among 

 some of the more important localities visited were 

 the famous Birmingham district, w^here oppor- 

 tunity was afforded for observing some of its more 

 important geologic features, including visits to 

 iron and coal mines, limestone quarries and indus- 

 trial plants ; the extensive iproductive graphite area 

 between Lineville and Goodwater, the largest do- 

 mestic producer of graiphite; the marble quar- 

 ries near Sylaeauga; and Sheffield and Florence 

 where are located the government nitrate plant and 

 prospective water-power developments at Mussel 

 Shoals on Tennessee Eiver. 



The geologists participating in a part or all of 

 the excursiions were : Eugene A. Smith and W. P. 

 Prouty (Alabama), J. A. Bownocker (Ohio), G. 

 F. Kay (Iowa), H. B. Kiimmel (New Jersey), I. C. 

 White (West Virginia), W. N. Logan (Indiana), 

 S. W. McCallie and J. P. D. Hull (Georgia), W. 



