CONTENTS. 
/ 
NOTICES AND ABSTRACTS OF MISCELLANEOUS 
COMMUNICATIONS TO THE SECTIONS. 
MATHEMATICS AND PHYSICS. 

Page 
Address by the President of the Section, Professor MACCULLAGH weccseessesssere 
Sir Witi1am Rowan Hamitton ona Theorem in the Calculus of Differences... 2 
——_—_—_— on some investigations connected with the Cal- 
culus of Probabilities ..........sseeseeceeseeenes sceeeepatos SRAGeis@audecactnssewscexansee | lo 
Professor Luoyp on the Method of Graphical Representation, as applied to Phy- 
sical Results .......sccecscseesenvees Orrin bebo basobe aardpocgcde asec aie aug bo abies ogupest ee ap 
_ Professor MacCuuiacu on the Theory of Total Reflexion, and of the Insensi- 
_ ble Refraction which accompanies it .......++++++ baa caaersenisighs eoeaderene ssccetayizenna 4 
Professor Luoyn’s Attempt to explain theoretically the Phenomena of Metallic 
: BPEPCHCKION, ....0ss:c0ne Rue ak Gladaien ae ance oils SM tottae taaivigns ta Datoaane linia Nove sees cas ena ioass eG 
Sir Davip BrewstEr’s Notice of an Experiment on the Ordinary Refraction of 
BRIAR SPAT 2c cccccqasareeng vesiece Erne? Capa yoncHeSBepaioe nckeeaceqaeeeePadee eeageratace: 7 

1 Professor MacCutiacu’s Remark relative to the preceding Notice sccsseccersoee 7 
_ Sir Davin Brewster on the Action of Two Blue Oils upon Light. 8 
j Sir Joun Herscunx’s Notice of a remarkable Photographic Process by which 


dormant Pictures are produced capable of development by the Breath or by 

Keepin dia Ioist ALMOSPHELe s...cs.corcoesndecscuesenccosev=scsccceevecscsenccsceseee 8 
Professor DrapEr on a Change produced by Exposure to the Beams of the Sun 
____ in the Properties of an Elementary Substance ...... “Bene SORE SCALES" Acer Got a 
5 Rey. Professor Powe. on Elliptic Polarization in Light reflected from various 
RUSTANCES SEL 056i2, cc eccsccakteace access Rpersasy Stine cen choehongcaer nectr retard toe OF 
om: Rosert Hunt on the Changes which Bodies undergo in the Dark .......... 10 
_ Dr. Greene on polishing the Specula of Telescopes .......... serecnssaccsdctegevetsa 11 
Sat 
k Professor Lioyp on the regular Variations of the Direction and Intensity of the 
__ Earth’s Magnetic Force .......sssssseveee Renee aeene na dataetuetiesed teresa as chaesgaeecae, be 
Rev. W. Scorzssy on the Circumstances which affect the Energy of Artificial 
IRE sss cetscecccceuccucd 4c satan eens edvecuyavaxs: cv<ure Teccentavcvacts caesar eumemity aed 
_ Mr. J. P. Joune’s Description of a Galvanometer .......... "er acer t pchelencn Sankeds 1 Lt 
_ Mr. Joun Nort on a new Electrical Machine, and upon the Electricity of the 
Atmosphere ...... Sitease cts sversdeacnere Bidoesceenes Saees dae scat gs cna haas eccqastcceseeeega’ CO 
Rey. Dr. Rosrnson on Determining the Index Error of a Circle by reflexion of 
| the Wires of its Telescope ............:.sccccceees avewansansssheceetaedssehee Sewutsccsees’ LO 
$ ——-———— on the Barometric Compensation of the Pendulum ..... Se 
Captain Larcom on Contour Maps ..... pete antes: sinban ates presetaneRenthaphascvucana’\- 18 
Mr. ALexanper Brown’s Account of the extraordinary Flux and Reflux of the 
Sea, July 5, 1843, at Arbroath ......sccsccessesscesees ace teeeaves iscicesevetes saan 18 
