PROCEEDINGS 1849 — 1858. 
259 
to their formation are discussed, the one accepted being that they are 
caused by the rock underneath being removed by running water, and 
the superincumbent mass of limestone falling in, leaving a circular 
hollow above. 
The annual meeting was held at Leeds in December, the Mayor, 
Mr. John Hope Shaw, in the chair. The treasurer's accounts were 
presented, and from them we gather that the principal items of 
expenditure were the assistant secretary's salary and the rent of 
Museum Rooms at the Philosophical and Literary Society at Leeds, 
a small balance remained in the hands of the treasurer. A paper was 
read by Mr. R. Solly, on Observations on the Manufacture of Iron. 
Tlie several sources of supply of the raw material were enumerated 
and considered, and the characters of the iron, principally malleable 
iron, were enumerated. A second paper was read by Mr. T. J. Pearsall, 
F.C.S., Consulting Chemist to the North Lincolnshire Agricultural 
Society, on the chemical preparation of Flax for manufacturing 
purposes. The paper was an exhaustive one, and described with much 
detail the growth of flax and its subsequent manufacture. 
Only one meeting was held in the year 1853, at Doncaster. 
Messrs. William Beckett, M.P., John Mc. Londesborough, and Peter 
Fairbairn were elected members amongst others ; and valuable papers 
were read by the honorary secretary, Mr. W. Sykes Ward, on a new 
Thermostat for regulating ventilation ; by Mr. H. C. Sorby, F.G.S., 
of Sheffield, on the Origin of Slatey Cleavage. After stating that 
Mr. Fox, of Cornwall, and Professor Hunt found that a laminated 
structure was produced by passing an electric current through clay, 
the author explained that a distinct relation had been found to exist 
between the direction of cleavage and the axis of elevation of a cleaved 
district ; several observers, chiefly Professors Pliillips and Sharpe, 
had shown that the organic remains found in slate rocks, indicate a 
considerable change in their dimensions, being compassed in a line 
perpendicular to the cleavage ; and Professor Sharpe strongly advocated 
the theory of the cleavage being produced by this pressure. Mr. 
Sorby had been for some time studying the microscopical structure of 
rocks, and being convinced that cleavage must be due to some pecu- 
liarity in the arrangement of the particles, he applied this method of 
