68 Scientific Intelligence. 



of a clear night without moon. The extreme limit for the penetra- 

 tion of day-light during the winter was something more than 200 

 meters. The difference between this limit for March and Sep- 

 tember was only some 20 or 30 meters, proving that the effect of 

 the seasons, so great in the upper layers of the lake, as shown by 

 M. Forel (this Journal for June, p. 495), is comparatively small 

 at considerable depths. In the Mediterranean, the depth is 

 greater. In the month of March it was found here that 400 me- 

 ters was the' limit of transmission of day-light. Further, subse- 

 quent experiment showed that at 300 meters the light reaches 

 during the whole time that the sun is above the horizon and at 

 350 meters this is true for some eight hours of the day. — Bibl. 

 Univ., Ill, xix, 442-447. 



9. A Treatise on Electricity and Magnetism; by E. Mascart 

 and J. Joubert, translated by E. Atkinson. Vol. ii, 792 pp., 

 8vo. London, 1888 (Thos. de la Rue and Co.). — The first vol- 

 ume of the English translation of this excellent work appeared 

 some four years since (this Journal, xxvi, 148). The present vol- 

 ume goes through the subjects of methods of measurements and 

 their applications, treating them with admirable thoroughness 

 and system. The general methods of measurements are first 

 taken up and then the special subjects of the theory and use of 

 electrometers, galvanometers and other electrical instruments ; 

 followed by magnetic measurements. A concluding chapter dis- 

 cusses the industrial applications as involved in electrostatic ma- 

 chines, dynamos, motors, etc. 



II. Geolog-y and Minekalogy. 



1. Geological Survey of Ohio : Economic Geology. Vol. YI, 

 /832 pp., 8vo. — Six hundred pages of this report are devoted to 

 / the subject of petroleum and natural gas ; and three-fourths of 

 these are by Professor Edward Orton ; the other fourth, consist- 

 ing of accounts of the methods of drilling wells, measurement of 

 wells, transportation, uses of gas and methods of using, and other 

 subjects of a practical character, are by Messrs. F, W. Minshall, 

 F. H. Newell, E. McMillin and Professor S. W. Robinson. The 

 remaining chapters treat of the Pittsburgh Coal-Seam, salt manu- 

 facture, cements, gypsum or land plaster, lime, and includes also 

 one on the Drift deposits of Ohio. 



Professor Orton opens with a new vertical section of the Ohio 

 rocks. The Trenton limestone is here recognized as one of the 

 outcropping rocks, Professor Orton accepting the conclusion of 

 Mr. S. A. Miller, that the beds of the Point Pleasant quarries, 

 about 20 miles above Cincinnati, are Trenton. Besides, the 

 Utica shale is separated by fossils from the Hudson River group, 

 and the term Cincinnati group is dropped. 



The form of the Cincinnati anticline, long since shown by 

 Newberry to have been made before the deposition of the Upper 

 Silurian, has been worked out by the numerous borings for gas 



