456 Bibliographical Notices. 



(p. 323), the very curve of whose tail enabled us to detect the true 

 value of the design, before we recognized in the corner the " hall- 

 mark " of Mr. Wolf's initials. 



Nothing disgusts a mechanic so much as to witness a loss of power 

 in an engine of any sort — a pulley unskilfully applied, a lever 

 acting at a manifest disadvantage, a pinion obviously misfitted. This, 

 then, is our feeling when we regard Dr. Hartwig's works. Here is a 

 German gentleman with an amount of application uncommon among 

 any but those of his own nation, having the advantages of a very 

 accurate accmaintance with English and of scientific tastes, who yet 

 will insist upon fitting out our countrymen with a knowledge of what 

 they either know already or may easily know of themselves. On 

 the other hand is a vast mass of scientific literature in a language 

 which comparatively few Englishmen comprehend, and which it 

 would be of the greatest use for them to understand. Why should 

 not Dr. Hartwig employ his powers in aiding them in this respect 1 

 Why should he not publish, in London, translations of some of those 

 valuable treatises which are still sealed books to English naturalists ? 

 We are not defending our ordinary educational course, we are but 

 simply giving utterance to a fact, when we say that a large majority 

 of our fellow-labourers in this country are unable to become acquainted, 

 except at a great sacrifice of time, with much that has been already 

 worked out, and oftentimes admirably worked out, by the industrious 

 brains of our Teutonic neighbours. 



Phosphorescence, or the Emission of Light by Minerals, Plants, and 

 Animals. By T. L. Phipson, Ph.D., F.C.S. London : Reeve 

 & Co., 1862. 12mo. 



The phenomena referred to by Dr. Phipson, in the little work be- 

 fore us, under the general term " phosphorescence," are of a very 

 varied nature, and can scarcely be regarded as all falling under one 

 category. They include all emissions of light which cannot be ac- 

 counted for directly as phenomena of electricity or combustion ; 

 nay, some even of the latter, such as the luminosity of phosphorus, 

 are considered as examples of phosphorescence by our author. Cer- 

 tain cosmical and meteorological phenomena, such as the zodi- 

 acal light, the apparent train of light left in the track of many 

 aerolites, luminous fogs, &c, are also mentioned as examples of phos- 

 phorescence ; indeed the author seems to have been anxious to omit 

 noticing no luminous phenomenon the cause of which cannot readily 

 be explained. Apart from all these doubtful instances, we have, how- 

 ever, a large number of phenomena to which no other term than 

 that of phosphorescence can be applied : there are numerous mineral, 

 vegetable, and animal substances to which the name of "light- 

 bearers" may with justice be applied, and the emission of light from 

 which is still entirely unexplained. We have minerals which give 

 out light after exposure to the sun, and others which present similar 

 phenomena when heated to a temperature far below that of incan- 

 descence. From others light is given off when they are rubbed or 



