EV CONTENTS. 
The voleanie sand which fell at Unalashka, October 20, 1883, 
and some considerations concerning its composition, J. S. 
AO SWC Oa de a ecg a ye ey Ee ee ee a 33 
The methods of modern petrography, G. H. William -___-_- 86 
What is a glacier? (Symposium) .--- ----- ---------------=-- 37 
The physical basis of phenomena, H. H. Bates ------ -----— 40 
The strata exposed in the east shaft of the water-works exten- 
BvOn ee EVO DUISON) 222 one ee eee oe ee ee 69 
Plan for the subject bibliography of North American geologic 
literature, G. K. Gilbert and J. W. Powell_.------ -----_-- phil 
Are there separate centres for light- form- and color-percep- 
tion’? “So Ri Burnett sass Sa Se ee ee ee 72 
Was the earthquake of September 19th felt in the District of 
Columbia ?~Ts Robinsont3=— 2 2 a2 ee 73 
Natural naturalists, Washington Matthews -__-__.---------- 73 
Resolutions on the death of Dr. Woodward -_-- ------------- 75 
The voleanoes and lava fields of New Mexico, C. E. Dutton ~~ 76 
Electric lighting, E. B. Elliott, (Title only) -----. ----—.- --- 80 
Thermometer exposure, H! ‘A. Hazen*l2 _L2 ---2 2-2 eae 80 
Presentation of the:annualaddress-2_ 222 SoU Sek See ee 81 
Axnual Meating 2202) eS ee ee eS eet ee ee 81 
Bulletin of the Mathematical Section” -.2- i 2- LS 2S sees 83 
Standing’ Rules of the Seetion=—— “2. Se ee ee 85 
Officers of ‘the: Sections. a eee 86 
Curves similar to their evolutes, C. H. Kummell -_----~----- 87 
The problem of the knight’s tour, G. K. Gilbert --_-------__- 88 
Empirical formule for the diminution of amplitude of a freely- 
oscillating pendulum, H. Farquhar ~__~__---_~. ------ -__- 89 
A concrete problem in hydrostatics, G. K. Gilbert_.-__-____- 92 . 
The formule for computing the position of a satellite, A. Hall- 98 
A formula for the length of a seconds-pendulum, G. W. Hill, 
( Pitlerortty) oa eee ee a 101 
A form of the multinomial theorem, A.S. Christie, (Title only). 101 
Discussion of a concrete problem in hydrostatics proposed by 
Mr. G. K. Gilbert, R. S. Woodward, (Title only) ---------- 101 
The quadric transformation of elliptic integrals, combined with 
the algorithm of the arithmetico-geometric mean, C. H. 
Kunimell) 42 ees ee eee eee ee 101, 102 
A case of discontinuity in elliptic orbits, W. B. Taylor____..§.§ 122 
The verification of predictions, M. H. Doolittle.-.------.---- 122 
Memorial to Gen. ‘Alvord (Set Ses ol eee ee 
Committees on mathematical communications_.._-_--.-------- 129 
Index 22223 a ne ee he en 
