102 Historical Sketch of Improvements in [Aug. 



Mix together one part of sulphur, two parts white oxide of 

 ■arsenic, and five parts of potash of commerce, and expose the 

 mixture in a crucible to a heat approaching to redness. Dissolve 

 this mixture in water, separating the sediment which consists of 

 ..metallic arsenic, and a chocolate coloured powder suspected to 

 be a subsulphuret of arsenic. Pour sulphuric acid into the solu- 

 tion, a fine yellow precipitate falls, consisting of sulphuret of 

 arsenic. Wash this powder sutHciently, and then dissolve it in 

 liquid ammonia, and add an excess of ammonia sufficient to 

 render the liquid colourless. Put the cloth to be dyed in this 

 liquid, and allow it to remain till it has become fully impreg- 

 nated. Then take it out, and e.xpose it equally to the atmo- 

 sphere. As the ammonia evaporates, the cloth assumes a fine 

 yellow colour, varying in intensity according to the proportion 

 of sulphuret of arsenic in the hquid employed. (Ann. de Chim. 

 €t de Phys. xii. 398.) 



I think that this yellow dye will not be able to withstand soap. 

 The alkahes would undoubtedly destroy it. Its use, therefore, 

 ■will be limited to those stuft's which are not to require washing. 

 JNow I rather suspect that dyers are already possessed of very 

 fine yellow colours ; but certainly of none finer than the one 

 proposed by Braconnot. 



II. Comparative Anatomy and Zoology. 

 By a Friend of the Editor. 



COMPARATIVE ANATOMY. 



A WORK on this subject, entitled " Philosophic Anatomique; 

 par M. Le Chevalier Geoffioy St. Hilaire,'" appeared towards the 

 €nd of the last year, in which the author attempts to prove the 

 truth of a theory advanced by him about 17 years since ; namely,, 

 that all vertebrose animals were formed, not only on the same 

 general plan, but that their skeletons consist of the same number 

 of parts. To be brief; that those bones which in fishes and 

 other animals at the lower end of the vertebrosa, remain sepa- 

 rate in the adult animal, may likewise be found in a separate 

 state in the young, belonging to the upper end of the same type. 

 We will now take a very general survey of the subject. 



GeoftVoy is of opinion that the bones of the ear (which, as everv 

 one knows, have been destroyed in both ears by disease, in the 

 human subject without loss of hearing to the individual), are to 

 be considered as but rudimentary in man, and other mammalia; 

 in the same way that the mammae are but rudimentary in the 

 male sex ; and that the said bones of the ear having reached 

 their highest degree of development in fishes, are represented in 



