TRANSACTIONS OF THE SECTIONS. 35 
that these are only occasional and minor phenomena in storms, and not the storm 
itself, as represented in the cyclone theory. He objected to the cyclone theory on 
the grounds that it is opposed to all the known natural laws which affect the con- 
dition of the atmosphere, as he believed it to be impossible that a disk of some 
hundreds of miles in diameter, but of a mere mile or so in thickness, of air lighter 
than the general atmosphere, could make its way for days and days in succession 
through the densest part of the atmosphere,—that the evidence in support of the 
theory is insufficient (this he attempted to show by the aid of diagrams from Reid’s 
‘Law of Storms,’ and a general reference to works of the kind), and that the phe- 
nomena of the (so-called) cyclone storms may be otherwise accounted for, 
On the Performance, under trying circumstances, of a very small Aneroid 
Barometer. By G. J. Symons, 
This instrument, which the author exhibited, had been worn constantly by him 
recently while at sea in rough weather, while riding and driving over roadless 
districts in the Orkneys, and also on several occasions when rough climbing and 
severe jumps had been necessary: he therefore presumed he might reasonably con- 
clude that it had been fully tried. It had been tested before, during, and after the 
voyage, and had in each case given the same result when compared with mercurial 
standards. He therefore inferred that it might be considered even less liable to 
derangement from travel than an ordinary watch. The instrument was very small, 
being only two inches in diameter and three-quarters of an inch thick, 
On the Disintegration of Stones exposed in Buildings and otherwise to Atmo- 
spheric Influence. By Professor James Toomson, M.A., C.E. 
The author haying first guarded against being understood as meaning to assign 
any one single cause for the disintegration of stones in general, gave reasons to 
show—lst. That there may frequently be observed cases of disintegration which 
are not referable to a softening or weakening of the stone by the dissolving away 
or the chemical alteration of portions of itself, but in which the crumbling is to be 
attributed to a disruptive force possessed by crystalline matter in solidifying itself 
in pores or cavities from liquid permeating the stone. 2nd. That in the cases in 
question the crumbling away of the stones, when not such as is caused by the freez- 
ing of water in pores, usually occurs in the greatest degree at places to which, by 
the joint agency of moisture and evaporation, saline substances existing in the 
stones are brought and left to crystallize. 3rd, That the solidification of crystal- 
line matter in porous stones, whether that be ice formed by freezing from water, 
or crystals of salts formed from their solutions, usually produces disintegration— 
not, as is implied in the views commonly accepted on this subject, by expansion of 
the total volume of the liquid and crystals jointly, producing a fluid pressure in the 
pores—but, on the contrary, by a tendency of crystals to increase in size when in 
contact with a liquid tending to deposit the same crystalline substance in the solid 
state, even where, to do so, they must push out of their way the porous walls of the 
cavities in which they are contained, and even though it be from liquid permeating 
these walls that they receive the materials for their increase, 
CHEMISTRY. | 
Address by Professor W. H. Mitime, 1.4., F.B.S., President of the Section. 
Once in about a quarter of a century a mineralogist is placed in the chair of the 
Chemical Section of the British Association. This procedure is not without its 
inconvenience: many important questions are likely to present themselves during 
the meetings of the Section which a mineralogical president can rarely be competent 
todecide, In another point of view, however, this arrangement is more satisfactory ; 
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