CONTENTS. 
* PAGE 
Proceedings; April 6th, 1891. Report of Committee on Scientific 
SOGLSiE Re on. ssc lshs Side ein Bre Gee Us ares A ae oe ere eae 113 
Blestion Gi: Me trbewra is: §) ees bac ees wee Pa eee 118 
Note on Rock Exposure at 148d and 144th sts. and Seventh 
Avenue,” “By ERRINRIOR RIMS @ccitiig vost eon eto wavsinns Sie etn 1138 
Note on an Economical Zinc Element for. Bunsen Batteries. 
By JW;;GOOLD,AsEVISON.... oncck oon eee euee er nes ee . 114 
Note on Photomicrographs from Photographs of Lightning. 
By: W... GOOLD: EVISON. 1.0 S2 ea oie ne ee oe Poe 114 
Proceedings: April.13th, 1691-2 2o ae eee oo ee eee 115 
Report.of Forestry Committée: o.ic<.. 25 ieee oie Sete hae 115 
Proceedingss-April-20thy 1801. .c¢.2 5 gk se ee eee 116 
Lecture. Practical Applications of Electricity. By “FRANCIS 
BM CROCKERS <b Moe eee Saat ae 7 pe lee Siatese tay dee eeaaie tet 116 
Proceedings: <A pril: 27th 1891.5 55 sk ova te ene eae ees 116 
Astronomical Section. 
Report of Committee on Permanent Organization........ 6. AAO 
Election of Officers. Saye traces PR oe ar Donen ke 116 
Stellar Photometry. By HENRY M. PARKHURST.............. 117 
Proceedings : May 4th, 1891. Election of Honorary Members...... 118 
Electric-Meters: By L; so, “LAUBY: S650 cea see eee 118 
Proceedings > May 11th; 1691 3. saggy ad See tee we eee Rees eo 118 
Proceediaes': ‘May 18th j160lc, tape Ata ores one oe eae eee 118 
Lecture. Whatisa Diatom? By C. F. Cox, A.M........ ... 119 
Proceedings May 25th 1891../2o.5 2 ukss eotupacs Se cepace ete epeeee LED 
Astronomical Section. 
The History of Lexell’s Comet from 1770-1890. By CHARLES 
EXAINH POOR Ge Svc isle aie vie Weolgca os oped ast eee te rae nec ae 119 
Proceedings : dune ist 1891) 3. icv ie se seas eee ee Me eee 119 
Obituary Notice of Dr. JoHN I. NORTHROP. ................. 120 
BHA Gas fo ae oot ieee ee “FO acaieM eek tesa w Gos Te ocak ein ee Rina oteewers 121 
