Notices respecting New Books* 221 



branch of popular science. The prefatory outlines of electricity 

 and magnetism are drawn up in a satisfactory manner; and the 

 Sketch of Electro-Magnetism itself, gives a clear and connected de- 

 tail of the principal observations and results of experiment, of which 

 the science at present consists, with an account of the various ex- 

 periments themselves, and directions for their performance. At 

 the close of the work is given a description of a series of apparatus 

 for exhibiting the most striking phenomena of electro-magnetism, 

 illustrated by three engravings in outline, by Turrell. 



There can be no doubt but that a second edition of this useful lit- 

 tle work will be called for; and when such is the case, we hope it will 

 be carefully revised prior to republication; for there are some inaccu- 

 racies in construction and language, and also in the occasional allu- 

 sions to the objects of chemistry and other sciences connected with 

 the subjects it explains, which, although they do not interfere with 

 the main utility of the work, are yet likely to mislead the student 

 in several minor, but still important points. We think, also, that it 

 would be preferable to incorporate the description of the electro- 

 magnetical instruments with the body of the work, giving each in- 

 strument in its proper place, as illustrating a certain part of the 

 science ; and in this case, engravings on wood inserted in the pages 

 should be substituted for the plates, as uniting greater facility of 

 reference, with equally satisfactory representation of the apparatus. 

 These remarks are made entirely with the view to the future im- 

 provement of what we consider a very useful contribution to scienti- 

 fic literature; and we hope the sale of the work will be such as to 

 encourage the writer to proceed in his endeavours to render the 

 study of electro-magnetism accessible to every class of inquirers into 

 the phenomena of Nature. It possesses one merit in particular, 

 in which elementary works are too often deficient, —that of citing 

 original and first-rate authorities on the subjects of which it treats, 

 instead of referring only to compendiums and compilations. Every 

 person, already possessing some elementary notions of experimental 

 philosophy, may obtain from the perusal of Mr. Watkins's treatise, 

 and the performance of the experiments described in it, a good ge- 

 neral knowledge of electro-magnetic phaenomena, and become pre- 

 pared for the study of the works in which their intimate nature is 

 investigated. 



We must not, however, conclude this notice, without adverting 

 to Mr. Watkins's remarks on the experiments of Professor Mori- 

 chini and Mrs. Somerville, in which steel, in various forms, exposed 

 to the more refrangible rays of the solar spectrum, acquired magne- 

 tic polarity. Mr. Watkins observes, " it is known that many of 



our most expert manipulators in experiments on natural philosophy, 

 have failed in repeating those of Morichini and Mrs. Somerville. 

 Hence we are led to infer, that the needles operated upon by Mori- 

 chini and Mrs. Somerville, possessed magnetic properties previous 

 to their being acted upon by the solar ray ; and that that magnetism 

 escaped the notice of the experimenters when tested by them at the 

 commencement of the operation." With the details of Morichi- 



ni's 



