CONTENTS. 



PAGE 



I. On the Young Stages of Bony Fishes. By Alexander 



Agassiz 1 



II. Experiments upon Piezometers used in Hydraulic Invesliga- 



lions. By Hiram F. Mills, Civil Engineer ... 26 



III. Researches on the Substituted Benzyl Compounds. Fourth 



Paper. By C. Loring Jackson and Alfred W. Field 54 



IV. The Development of Lepidosteus. By Alexander Agas- 



siz 65 



V. Researches in Telephony. By Professor Dolbear . . 77 



VI. On Certain Remarkable Groups in the Lower Spectrum. By 



Professor S. P. Langley 92 



VII. On the Temperature of the Sun. By Professor S. P. 



Langley 106 



VIII. On the Heat Produced by the Rapid Magnetization and De- 

 magnetization of the Magnetic Metals. By John Trow- 

 bridge, S.D., and Walter N. Hill, S.B 114 



IX. Methods of Measuring Electric Currents of Great Strength ; 

 together with a Comparison of the Wilde, the Gramme, 

 and the Siemens Machines. By John Trowbridge . 122 



X. Descriptions of some New Species of North American Mosses. 



By Leo Lesquereux and ThOmas P. James . . . 133 



XI. Distributions of Heat in the Spectra of various sources of Ra- 

 diation. By Wm. W. Jacques, Ph. D 142 



XII, On the Limits of Accuracy in Measurements with the Micro- 

 scope. By Professor Edward W. Morley . . . 164 



