CONTENTS. Xill 
. A System of Invariants for Parallel Configurations in Space. By Pro- 
FESSOLTAY. His, FORSYTH) SCIDs, BRASS: cic cncocsevethectcuasvecesvevecresecendesecs 640 
. On the Notation of the Calculus of Differences. By Professor J. D. 
PVMRE DD BY ER: Siedsaieadvensseesticgcesses sot cbeset Genenecedsacdwaersclocee suse addeves 645 
. On the Partial Differential Equation of the Second Order. By Professor 
ha (Oh LOURGXOR EN Hesse Ase nae oi t-te Oi nears ae Sen ria Ae ean Rt re nD Re 646 
. On the Fundamental Differential Equations of Geometry. By Dr. Irvine 
SBR UNG ARES. ae ee oie se ede int cae wiacnoass Rao acaune connec ees seower snes Moeadacen ses 646 
8, Report on Recent Progress in the Problem of Three Bodies. By E. T. 
RN PUUM MR YN Asanaavaccussasetarssncsweser astcensSenteatonesterntrese ses suuaoocte ces 647 
9. *On Singular Solutions of Ordinary Differential Equations. By Professor 
AC SEU ME ORSYTH, SCD ys Hs EUIS) 4. cd coeisvcoet dre fecadaecedee tena cacavwuse ores agcendae 647 
10, An Application and Interpretation of Infinitesimal Transformations. By 
Peeoredsor Pn Oy MOVE UIt s5¢. .oiees seid sbsueeiWuibadecads. teas. dd dkavmetuepsnecstaneane 648 
11, On Fermat’s Numbers. By Lieut.-Col, Anan Cunninenay, R.E. ...... 653 
DepaRtMENT IT.--MErEoROLOGY. 
1. Interim Report on Solar Radiation ..........s..cccsessessccsessreceveneesensepeces 654 
2. On a Connection between Sunspots and Meteorological Phenomena. By 
Pe VAN, HIJOKEVORSUD sang cs ack Paget da Keaahawerennaidiha dn eavaasiceny-aaeevelones 654 
S. Report on Seismology.........ssesssecessssrssesesserssanerssreeccssssssssesessarsees 654 
4, Seismology at Mauritius. By T. F. Craxton, F.RB.AAS, «0.0... cee eeee eee 654 
5, Progress in Exploring the Air with Kites. By A. LAwrencz Rortcn, 
8. B, ATA aes ele side's civh'a's Uullablelnbe sat Moe nde UaseOt ei ateae doaay coats arene shadadeuse 655 
6, Remarks Concerning the First Crossing of the Channel by a Balloon, 
By Ay GAWRENCH ROTCH, 82: Ac Mirscasiesasn'sa ss iasestenatencevanersieconssioveun 656 
7. The Hydro-Aérograph. By F. Naprer Denison, Victoria, B.C............. 656 
8. Report on Meteorological Observations on Ben Nevis ..........seceecseeeeeee 658 
9. Report on Meteorological Photography .........ccsccseseceeecneceescsseeceeenees 658 
10. Report on the Meteorological Observatory, Montreal............sseccesaeeeenee 658 
11. The Rainfall of the South-Eastern Counties of England. By Joun 
Hoprxinson, F'.R.Met.Soc., Assoc.Inst.C.H......csccsssccsssconsscessccsevgeescens 658 
TUESDAY, SEPTEMBER 19. 
1. ¢On a Gravity Balance. By Professor R. THretratt, F.R.S., and Pro- 
PEBBOE Ss Wy OLLOGKeccyarenes .tvnnelecids<habdcauae comp dvaips vughied te naeide pppddveyss 659 
Pr hreport On Electrical Standards... ..2.0c.vsevsccoessvosecusvensieccsonsctsebssonesgas 659 
8. Discussion on Platinum Thermometry ......ccs.sccsccsesecegecceeetensessesesencs 660 
WEDNESDAY, SEPTEMBER 20. 
1. Recent Magnetic Work imNorth America. By L. A. BAUER ..eeecseese 660 
2. The Spectral Sensitiveness of Mergury Vapour in an Atmosphere of 
Hydrogen, and its Influence on ‘the Spectrum of the latter. By E. 
IPEROIVAT Du WAS, PID fice iek ttc ded bacemace cbavouetevssecies «es soewseaetienstel« 660 
. On the Theory of the Electrolytic Solution Pressure, By R, A. Lzu- 
TELL eS Asc bbe DE DAC OSCE e SUL CO ES ACUIMAC HE ACE Cerio er Pe AI crn Aas Ss ats La 661 
Temperature and the Dispersion in Quartz and Calcite. By Tees 
GIFFORD .3,.,....00000% np ayh hes ABCC Tava tie Ganieeh lek Haare PECrG Serer: Goes 661 
