CONTENTS. 



Page 

 I. Studies in the Eupatorieae : (I.) Revision of the Genus Piqueria ; 



(II.) Revision of the Genus Ophryosporus ; (III.) The Genus 



Helofjyne and its Synonyms ; (IV.) Diagnoses and Synonymy of 



Eupatorieae and of Certain Other Compositae which have been 



Classed with them. By B. L. Robinson 1 



II. Architectural Acoustics: (I.) Introduction; (II.) The Accuracy 



of Musical Taste in regard to Architectural Acoustics ; (III). 

 Variation in Reverberation with Variation in Pitch. By W. C. 

 Sabine 49 



III. On the Permeability and the Retentiveness of a Mass of Fine Iron 



Particles. By B. O. Peiece 85 



IV. On the Length of the Time of Contact in the Case of a Quick Tap 



on a Telegraph Key. By B. O. Peikck 93 



V. Sojne Stages in the Spermatogenesis of the Honey Bee. By E. L. 



Mark and M. Copeland 101 



VI. Friction and Force due to Transpiration as Dependent on Pressure 



in Gases. By J. L. Hogg 113 



VIT. On the Conditions to be Satisfed if the Sums of the Corresponding 

 Members of Two Pairx of Orthogonal Functions of Two Vari- 

 ables are to be Themselves Orthogonal. By B. O. Peirce . . 147 



VIII. On the Correction for the Effect of the Counter Electromotive Force 

 induced in a Moving Coil Galvanometer when the Instrument is 

 used Ballistically. By B. O. Peirce 159 



IX. A Simple Device for Measuring the Deflections of a Mirror Gal- 

 vanometer. By B. O. Peirce 171 



X. On the Cytology of the Entomophthoraceae. By L. W. Riddle . 175 



XI. A Revision of the Atomic Weight of Bromine. By G. P. Baxter 199 



