:' IMAGE EVALUATION TEST TARGET (MT-3) 1.0 1.1 11.25 Uj ^^ ■■■ ■tt Uii 12.2 £^ U£ 12.0 lit wuu Photographic Sciences Corporation •a WIS'. HAW sriiin W«t:i:ill.N.V. 14SiO (7U> 173.4901 ' > CIHM/ICMH Microfiche Series. CIHM/ICIVIH Collection de microfiches. Canadian Inatituta for Hiatorical Microraproductiona / Inatitut Canadian da microraproductiona hiatoriquaa Technical and Bibliographic Notas/Notaa tachniquaa at bibiiographiquaa Tha totl^ Tha Instituta has attamptad to obtain tha bast original copy availabia for filming. Faaturas of this copy which may ba bibliographically uniqua, which may altar any of tha imagas in tha raproduction, or which may significantly changa tha usual mathod of filming, ara chackad balow. □ D Colourad covars/ Cou ,; ••'.•^.■.■, 1?, ^... •J ■) ( . '. ■^j'v.-^:^-!^ .iii'i^ '^A.:'.^-f', ■■d^ 'i^^^tj'V ;•■;,./•.'. V''/; . ! '■' .A ■.f-f ^, .. I/,- ■ r; . ■ : , ■" ^ .'.'?'.■ ,x. .'^'^■^ a /'.i . / ;'^^: . -'',.-1 M^r :^'\' ' ■ 1 • .1 ■■/■... . A ,', , : 1 ■ •■■ ■ ■ :' •■ ^ ■■ ■' - V.A..., ..V ^_. z^"'''- ; i ■>. '• ' , « 'f ' \ ',1 1 :' ■, .. , 1899.] NATURAL 8CIf:NCES OF rillLAnELl'IIIA. 501 ADDITIONAL OBSEBVATIONS ON GLACIERS IN BRITISH COLUMBU. •- r BY CJKOUOK AM) WII-MAM H. VAl X, .IK. .^ ': 'J-'. 'd .v:/':i ., Vv ,>^ .<.'.■., V-.. . -,■ -* ir.^■^ ji '-• ■ , ;:^. fM ;.vn;i:'- -/, -y 1 .y-' ■ ^.''it > ■'' ,\ i . ;■ ■, - . • Ti .a, .' i • f.. <.',.';,.' ,J _, v. ' Excluding the territory which lies to the north of the Arctic Circle, all the priucipor> ILl-i:Ci:i,LEWAKT GLAIIKR. Owing to ita Bccessihility, this glncicr has bccn'more carefully observed than any other ui the region. It niay.be reached by ii good trail iu thirty ininuti'S from Glacier House, and wo visited it almost daily between the 'JUth of July and the 20tli of August of the present year. During this period, partly owing to the cold and damp weather, but little melting or recession of the totiguc was noted. This was in marked contrast to the rate of melting observed last year.' The observations on this glacier naturally divide themselves under four principal heads, which will be taken up us follows: 1. Measurements of rate of flow. 2. Measurement of recession and other changes since |1 898. 3. Photographic record from test rock •* AV 4. Survey of tongue, and mapping moraines and titreams. 1. MeaBurements of rate of flow. These were determined at nine points on the glacier, one a few feet above the tongue, and eight on a straight line at right angles to the flow and about 1500 feet above the tongue. Rev. Wni. S. Green, in 1888,'' made a determination of tlie rate of flow by driving stakes into the ice iu a direct line. Owing to the rapid melting, however, these soon fell, and when he returned to reraeasure, no accurate results could be obtained. Profiting by his experience, wo decideii to employ plates of steel, six inches wiuare and one-eighth inch thick, in the centres ui which holes were bored and threaded to receive three-quarter-inch pipes, three inches long. The origimxl purpost of the pipes was to supjwrt small flags to facilitate observation. It was found, however, A\hen the practical test came to be made, that if the plates were inverted, Avith the pipes extending on the under side, they sank into the ice, forming anchors, while the plates rested on the surface and could be easily seen. The plates were given two coats of vermilion paint, and lettered and numbered in white for identification. The right moraine of the glacier being "high and secure, and » Proc. Acad. Nat. Sci. Philu., 1899, p. 123. * Among the Selkirk Glaciers, p. 218. I iM rm PROCKEDrxos OF THE ACADEMY OF [1899. affording an excellent view of the surface of the ice, we deter- nnned to use its ridge as tiie station for tiie transit. Observations ]iad l)een made to determine the moan direction of flow of the ice and on the 31st of July, 1899. the transit was adjuste.l on the ridge. A large tree was taken as a line mark on the left side of th(! valley. The plan of measuring a distance of 250 feet between the plate, by means of a tape measure was proved to be impracticable on going on the ice. While the surface was comparativelv smooth it was rolling an,l broken by valleys running at right angles to the direction in which the measurements were to be made. In nearly ev^ry case it was not possible to see from one plate to the next \ e accordingly decided to abandon the actual measurement, and after a.ljusting the plates, to lay out a base line and take the angles to the plates from each end. The results could then be plotted on the map and the distances obtained. This plan worked well, and on the second visit Ave were able to place a transit at each end of the base line, and make readings of both andes at tiie same time. Eight steel plates were laid out on the line shown on the map At t us point the total breadth of the glacier is 1720 feet Owin<. to the roundel surface of the glacier the position for the ninth plate was not visible from the ends of the base line, and as it was quite Close to the left border it was omitted altogether. On the 11th of August, or eleven days later, transits were set up at each end of the base line and the bearings to each of the plates taken. At the same time the exact movement of the plates was accurately measured from the direct line in which they had originally been placed. This will be found noted in the fourth column of the tal)le. i9 18f»l».] NATURAL HCIKXCKS OK PHILADELPHIA. 507 Table shoiciiui Motion of Line of Plates, across lUecellewnet Glacier, British Columbia, Jitly 31st to September 5th, IS'JO. Number of Plate. Feet tVoii N. Border 1 Dales of Observation, ( July 31 ; Motion since last Obs. (ins.). Oil Hue. 1 ) veroRe diiih notion (Ins.) 1 265 \ Auf,nist 1 1 42.5 f 2.56 ( Heiilenibcr 5 31.5 f ( July 31 On line. ) 3 500 \ August 11 40 f 3.90 ( Scj)ton)l)t'r 5 \VX )' f 1 July :!1 On line. I 3 605 < ! Augu.st 11 75 5.51 ( j Septi mher 5 105 i r July 31 On line. ) 4 7r>o j August 11 ( Septeuiber 5 74.5 Lost. } 6.77 f July 31 I August 11 On line. ) 5 845 71.5 f 6.06 1 September 5 , 140.5 ) f July 31 ' \ .August 11 ( September 5 On line. ( 6 980 76.5 1 6.79 165.5 f July 31 On line. 1 7 1040 i \ August 11 60 6.16 I September 5 172 ) 8 1310 f July 31 ■j August 11 On line. m I 6.00 1 • September 5 Lo.st. Again, on September o, tlirougli the kinrlne.-s of Ur. E. J. Duchesnay, of TIevelstoke, B. C, another measuninient wa.s niaile by ^[es.