612 
PHILOSOPHICAL SOCIETY OF WASHINGTON. 
Page. 
British northwest, Physical features of a por¬ 
tion of. C. A. Kenaston. 507 
Brocken spectre. H. A. Hazen. 550 
Burial mounds of Japan. R. Hitchcock. 553 
Burnett, S. M.: Models showing refraction by 
cylinders with their axes crossed at vari¬ 
ous angles. 531 
— New metric system of numbering prisms.. 
Cajori, F.: Difference between Napier’s and 
natural logarithms. 603 
Carr, W. K., elected member... 568 
Cattle, and meat inspection, Objects and 
methods of. D. E. Salmon.. 569 
Chapman, D. C., elected member. 522 
— New form of galvanometer. 540 
Chart-making. H. G. Ogden. 554 
Chemical action between solids. W. Hal- 
loek. 542 
Chemical elements, Relative abundance of. 
F. W. Clarke.. 131, 542 
Christie, A. S.: What is a Quaternion ?. 579 
Clarke, F. W.: Determination of atomic 
weights. 506 
— Gem localities of Maine. 570 
— Relative abundance of the chemical ele¬ 
ments. 131, 542 
— Theory of the mica and chlorite groups... 568 
Coffin, J. H. C., Death of.. 550 
Colonna, B. A., elected member. 555 
Color perception. H. V. Wurdemann. 531 
Columbian formation, Southern extension 
of. W J McGee. 550 
Comet 1888 V. W. C. Winlock. 601 
Committee on communications, 1888. 499 
-1889. 528 
- 1890. 550 
-1891. 564 
— on publications, 1888. 499 
-1889 528 
-1890 550 
-1891. 564 
Constitution, Amendment to, proposed.. 518, 527 
Cope, E. D.: Relation of consciousness to 
animal motion. 518 
Corrasion, Laws of. J. W. Powell. 519 
— Remarks on the laws of. L. F. Ward. 519 
Croffut, W. A.: Experiments in hypnotism... 516 
Cross, W.: Constitution and origin of spher- 
ulites.411, 568 
Crystallization of igneous rocks. J. P. Id- 
dings.. 65, 541 
Curtice, C.: Cambrian rocks in Tennessee... 516 
Curtis, G. E.: Hot winds of the Plains. 564 
— Rain-making experiments in Texas. 570 
— Relation of surface and climatic condi¬ 
tions to the flow of water-courses. 552 
Curve of pursuit. A. Martin.. 608 
Page. 
Dali, W. H.: Some forms of the gill in pe- 
lecypod mollusca. 541 
— Obituary notice of Emil Bessels. 465 
Dawson, G. M.: [Explorations in northern 
part of British Columbia and head-waters 
of the Yukon]. 502 
Deaf, Education of the. E. M. Gallaudet. 570 
— New Departure at Kendall Green. J. C. 
Gordon. 57T 
Deaf-mutes, Discovery and development of 
hearing in. J. C. Gordon. 539 
De Caindry, W. A.: Treasurer’s report, 1891. 574 
Decimal system of the 17th century. J. H. 
Gore. 556 
Delaunay, Error in. C. H. Kummell. 604 
Differential equations, Application of infinite 
determinants to the integration of. G. 
W. Hill. 601 
Diller, J. S.: History of porphyritic quartz 
in eruptive rocks. 531 
— Sandstone dikes of northern California... 543 
— Secretaries’ report, 1889 . 544 
-1890. 557 
-1891. 572 
Dividing engines. J. E. Watkins.. 554 
Doolittle, M. H.: Applications of a formula 
for the probability of an event resting on 
concurrent testimony of two witnesses.. 604 
— Means and averages. 596 
— Probabilities. 583 
— Problem in probabilities .. 602 
— Symbols of non-existence. 603 
— Two problems in probabilities. 605 
— What is force?. 589 
Dutton, C. E.: Irrigation in the arid region. 542 
— Money fallacies. President’s address, 
1890 [1891].359 
— Remarkable transcendental equations. 607 
— Some of the greater problems of physical 
geology... 51, 536 
Dynamics, Problem in. R. S. Woodward. 605 
Eakins, L. G., elected member. 551 
Earth, Interior constitution of, as respects 
density. G. W. Hill. 581 
— Figure of Study of, by means of the pen¬ 
dulum. E. D. Preston. 567 
— Mass of, mechanical conditions of. C. 
Abbe . 533 
— Mass of, mechanical conditions of. R. S. 
Woodward..'. 532 
— Mathematical theory of the stratum of no 
strain. R. S. Woodward. 602 
— Variation of terrestrial density, gravity, 
and pressure. R. S. Woodward. 580 
Eastman, J. R.: Assumption and fact in the 
theories of solar and stellar proper mo¬ 
tions. President’s address, 1889. 143, 543 
