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CON TEN TS.
J. T. Pettigrew, F.R.S., F.S.A., &c.
Report of Magnetical Experiments on board an Iron Steam Vessel. By Ed-
ward J. Johnson, Esq., Commander R.N., F.R.S.
Improvements in Steam Carriages on New Term in Physics
New Fact in Electricity
169 Mode of ascertaining the Proportion of
Steam-Boilers. By M. Galy Cazalat 173 Investigations, &c., recommended by
Huttonian Theory of Rain controverted 331 Melloni
Wanton Destruction Annually of a Mirage in Iceland
MAGAZINE OF POPULAR SCIENCE,
JOURNAL OF THE USEFUL ARTS.
A POPULAR COURSE OF GEOLOGY.
INTRODUCTION. Sir John HERSCHEL has said that Geology, in the magnitude and sublimity of the objects of which it treats, ranks in the scale of the sciences, next to Astronomy; to which we may add, that it will ever be more generally cultivated, because a knowledge of it is more easily attainable. It may be successfully pursued without that severe preparatory discipline of mathematical study which is required of the votaries of astronomy, before they can advance even to the threshold of her temple. In making this assertion, we by no means deny the dependence of geology on the other sciences; we admit, on the contrary, that he who would be a perfectly accomplished geologist, ought to be familiar with the whole circle of them. He ought to be thoroughly versed in mathematics and general physics, in order that he may know what are, and what are not, sound data on which to found his inferences—he ought to be skilled in mineralogy, that he may know the proximate constituents of rocks. Of the general results of chemistry he must not be ignorant, and he will find it a great advantage to be expert in chemical analysis. The organic remains entombed in the strata, will make constant demands upon him for a knowledge of zoology in all its branches, and in particular he ought to possess such an intimate acquaintance with those nice distinctions which constitute specific differences in conchology, as of itself requires the study of a whole life, and such a profound knowledge of comparative osteology, as enabled Cuvier, from the examination of detached bones, to remodel the entire skeletons of animals of unknown genera: such is the harmony of proportion, the adaptation of means to ends, and of parts to uses, which the wisdom of the Creator has manifested in the structure of organic bodies. The geologist ought moreover to be a botanist of the highest order, and in the most extensive sense of the term. He ought to be able not merely to refer a plant to its place in some artificial system, by counting its stamina,-a process which he will rarely, if ever, have an opportunity of applying to the fossil vegetation of former worlds-he ought to be able, from the examination of a stem, a leaf, or a seed-vessel, to determine the natural group to which the plant belongs, and by pointing out its habits, to throw light on the circumstances under which the stratum containing it was deposited. He ought, moreover, to be a good draughtsman, and a skilful practical surveyor. Acquirements so varied and extensive as these are attainable by few, and yet much may be done in geology with a very limited proficiency in these branches of knowledge. Without a very profound acquaintance with any of them we may master Vol. II.