234 



REPORT OF COMMITTEE ON GEOLOGICAL SURVEY. 



[1855. 



served as axes to prisms, and which now derived accession from 

 tlieir half-fluid and dissolving matter. In this manner they 

 continued to exchange one simple form for another yet 

 more simple, until the pristine drop of water occupied the 

 site of the former crystal. At llh. IComin. snow was 

 falling quickly in minute crystals as described. The air was 

 geniaf and mild, the clouds lightened as preparatory to sun- 

 shine, and the birds for awhile sang joyously. All nature 

 seemed to rejoice in the mitigation of the weather. At 12/j. 

 the snow had all but ceased, and the temperature was 37°. The 

 cocks crowed as anticipating a change ; the birds answered each 

 other from the trees ; icicles, two feet in length, which had 

 been noticed for sixteen days previously, began fast to melt 

 away. All nature, but the birds, was still ; and, what is rare- 

 ly seen, the trees were dripping moisture while the snow lay 

 like a rime upon their branches and bended stems. At l/i. 

 13m.. the temperature was 35°. 5, and small and fine snow was 

 again falling ; water was dripping everywhere, the birds were 

 singing joyously, and the calm continued. After a short in- 

 termission, the cold set in again, but with much abated rigour ; 

 and on the mornings of March 8, 9, and 10, with a tempera- 

 ture a few degrees above the freezing-point, Mr. Glaisher ob- 

 served a number of stellar crystals, made up almost entirely of 

 spicute and half-dissolving prisms. They were between 0.3 in. 

 and 0.4 in diameter; they fell sparingly, without snow, some- 

 times singly, but more often in groups of tliree or four toge- 

 ther. The collapsing, which would seem to be a method of 

 change peculiar to a temperature below freezing, was not wit- 

 nessed on this day ; but the process of dissolving at a tempera- 

 ture above 32° was seen to great perfection. The outer and 

 boundary line of each figure, and its component parts, became 

 exchanged for curved lines, bending inwards, whilst the crys- 

 talline matter, every instant becoming more watery, ran out at 

 the angles of the prisms in the form of spicute. The prisms 

 of the crystals, thus in a transition state to their original fluid 

 medium, presented each an exact similitude to a holly leaf, and 

 as being made up of curved lines a very anomalous appearance. 

 This change was not always simultaneous, sometimes commenc- 

 ing at either or both ends of the radii. There is room for 

 much examination and study respecting the manner of the 

 dissolving of these bodies, which under some circumstances 

 would doubtless show a reversal of the conditions under which 

 they were originally formed and attained their compound figure. 

 The author^ next proceeded to give a brief summary of each 

 day's observations. On Feb. 8, they commenced with a tem- 

 perature of 29°, which subsequently increased to 32°, at which 

 the temperature continued for many hours. During the 

 whole of this time, conspicuous for its uniform temperature, 

 the prevailing figure of the crystals continued to change, until 

 towards the close of the day they fell mingled together in the 

 greatest profusion. In the early part of the morning, it will 

 be remembered that they were arborescent ; that these forms 

 suddenly ceased, and were exchanged for hexagons ; that these 

 again became the centre of a more complicated arrangement ; 

 that after a time these diminished in numbers, when the arbor- 

 escent form again prevailed, and finally a mingling of nearly 

 all that had previously fiillen. On Feb. 16, with a tempera- 

 ture of 26°, there were two distinct orders of crystals, those 

 which were arborescent and exhibited an intermediate forma- 

 tion, and those of cruciform character, of solid hexagons cut 

 into numerous facets. Feb. 17, with a temperature of 32° 

 throughout, exhibited figures, it will be remembered, composed 

 of elongated prisms, ranged parallel to each other, and of very 



similar character. There were, however, exceptional instances 

 of the prevailing character of Feb. 16. On Feb. 21, with the 

 lowest temperature, viz. 20°, the figures were singularly com- 

 pound, and departed more than on any previous day from the 

 figure of the regular hexagon.- On leb. 23, the last day of 

 the frost, there were a large number of aborescent crystals of 

 one common character, and which never ceased collapsing into 

 more and more simple figures. On March 8, after a week's 

 respite, the cold set in again. The crystals on this and the 

 next two consecutive days, were of a very distinctive class, of 

 purely stellar figure, and composed chiefly of fine spicula. 

 From these ob.servations it would seem, that however tempera- 

 ture may affect these bodies, it is more than likely that other 

 conditions of a difiercnt nature are involved in their first for- 

 mation. This, apparently, was the view taken by a writer on 

 the subject in the Phil. Trans, for 1672. Speaking of snow 

 crystals (says the Rev. G. Langwith), " It is not easy to deter- 

 mine whether these figures may not be the result of the chemi- 

 cal components of the atmosphere, which as they preponderate 

 may not under certain conditions of temperature give rise to 

 these curiously simple and compounded bodies. Dr. Small- 

 wood, of Isle Jesus, Canada East, imagines them to be inti- 

 mately connected with the electrical states of the atmosphere, 

 whether negative or positive. The foregoing observations 

 show a wide difference between the various orders gf crystal- 

 line formation, and it would seem from them that the greater 

 the degree of cold the greater the departure from the simple 

 star, with all its variously arranged spiculas : also that shortly 

 after the descent of a crystal, at any temperature below the 

 freezing point, various processes of change take place, which 

 are evidently an undoing, if not a reversal, of the operations 

 which had assisted in their formation. These changes, through 

 which every crystal never fails to pass, even at temperatures 

 very many degrees below the freezing point, each more de- 

 structive than the last of its crystalline and compound figure, 

 led the author to the same conclusions. The subject of snow 

 crystals has engaged the attention of Aristotle, Descartes, 

 Grew, Kepler, Dr. Nettes, Dr. Scoresby, and others, but like 

 most subjects of meteorological inquiry, it has languished for 

 want of extended and continuous observation. The published 

 information concerning them is, however, likely soon to derive 

 accession from Sir Edward Belcher's observations made in 

 the Arctic Seas. Coming from this experienced and able 

 officer, they will be of substantial benefit to the inquiry into 

 the nature and circumstances of formation of these interesting 

 bodies 



The Geological Survey of Canada.* 



The Report of the Select Committee on the Geological Sur- 

 vey of Canada is a very important and valuable document, and 

 we lose no time in presenting the main features of the Report 

 before the readers of the Canadian Journal. 



The minutes of evidence occupy above sixty pages of royal 

 octavo, and contain much useful and curious information, 

 mingled, of course, with matter irrelevant or detriment to 

 the purposes of the enquiry. 



We confine ourselves, in the present instance, to the Report 

 itself, proposing to advert to the evidence in the next number 

 of the Jownal. 



* Report of Select Committee on the Geological Survey of Canada. 

 Printed by order of the Legislative Assembly. 1855. 



