Chemistry and Physics. 385 



ties of water vapor formed in the positive column .and in the 

 cathode fall were in the ratio of 4*5 to 6. — Phil. May., March, 

 1907. .t. t. 



11. Radio-active Matter in the Earth and the Atmosphere. — 

 Observers differ in regard to the amount of this matter. A. S. 

 Eve, Phil. Mag., September, 1903, came to the conclusion that a 

 proportion of l*8XlO -11 gr. of radium bromide per c.cm. uni- 

 formly distributed in the earth's crust is necessary for the pene- 

 trating radiation observed in the atmosphere. This is about four 

 times the average amount found by Strutt in rocks. G. A. 

 Blanc, Ph.D., of Rome, desirous of obtaining the relative 

 amounts of radium and radio-thorium excited activity in atmos- 

 pheric air in Rome and its surroundings, exposed an insulated 

 brass wire about twelve meters long electrified to 500 volts for 

 three days. It was found that the excited activity of the radio- 

 thorium type represents generally a large part of the total 

 amount exhibited by the wire, precisely from 50 to TO per cent. 

 Experiments were made on the terrace of the Physical Institute 

 in Rome, in a garden at a certain distance from the city, and in 

 the Catacombs of Saint Agnes near Rome, which are dug in the 

 volcanic formation pozzolana. — -Phil. May., March, 1907. J. t. 



II. Geology and Mineralogy. 



1. Manual of the Geoloyy of Connecticut ; by William 

 North Rice and Herbert Ernest Gregory. Bulletin No. 6, 

 Connecticut State Geological and Natural History Survey. 

 Hartford, 1906. 273 pp., 31 pis., 22 figs. (10 maps). — This is the 

 first complete presentation of Connecticut geology since the 

 report of Percival in 1842. While thoroughly scientific in its 

 method of treatment, it is yet divested as far as possible of tech- 

 nicalities and contains introductory portions on the cycles of 

 erosion, principles of metamorphism and the origin of the rock 

 types, enabling readers with only a slight knowledge of geology 

 to read the volume intelligently. This method of treatment is in 

 conformity with the purpose of the work, which is not only to 

 record the present progress in the geological knowledge of the 

 state for the use of other geologists, but to make a volume use- 

 ful for general educational purposes within the state. This last 

 object cannot be too highly commended. The present volume, 

 written by men who have spent years in studying Connecticut 

 geology at first hand, and designed for the intelligent layman as 

 well as the professional geologist, is doubly valuable. 



The information contained in this volume is in large part 

 derived from field studies by the authors themselves supple- 

 mented by the observations and writings of others, to whom 

 proper acknowledgment is made. Among these other names 

 may be singled out those of J. G. Percival, J. D. Dana, W. M. 



