| Description | Mallet briefly traces the history of geological opinion on this subject and points out that no clear and definite theoretic views have been enunciated to account for prismatic structure in basalt, and that it is impossible to gather, with any distinctness, from systematic writers, whether prismatic structure is due to contraction by cooling alone, or whether the structure is due to pre-existing concretionary or crystalline arrangement of the integral particles of the mass, or to this coacting with enormous external pressures, the origin of which is left perfectly vague, or to some play of successive and joint actions of all these various forces. James Thomson has proposed views, in some respects new, tracing prismatic structure to contraction by cooling only, and has expressed entire doubt as to the part supposed to be played by concretionary spheroids pressed together. Thomson’s views, however, are still far from complete, and the mode assigned by him to the production of cup-shaped cross joints in the prisms fails to account for the phenomena.
Annotations in pencil and ink throughout. Marked on front as 'Archives June 17/75'. Includes 20 pages of figures and diagrams relating to the structure of basalt.
Subject: Chemistry / Geology / Engineering
Received 12 December 1874. Read 21 January 1875.
Whilst the Royal Society declined to publish this paper in full, an abstract of the paper was published in volume 23 of the Proceedings of the Royal Society as 'On the origin and mechanism of production of the prismatic (or columnar) structure of basalt'.
A version of this paper was published by Mallet in The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science: Mallet, Robert. 'On the origin and mechanism of production of the prismatic (or columnar) structure of basalt.' The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, volume 50, number 329 (1875), pp. 122-135 and volume 50, number 330 (1875), pp. 201-226.
An abstract of this paper was published by Mallet in the American Journal of Science and Arts: Mallet, Robert. 'Abstract of a Memoir on the Origin, and Mechanism of Production, of the Prismatic or Columnar Structure of Basalt.' The American Journal of Science and Arts, volume 9, number 51 (1875), p. 206. |