3W- New Scientijic Books. [May, 



are stripped of the bark, and the surface made, of course, tolerably 

 smooth. The tree is launched with the root foremost into the steep 

 part of the trough, and in a few seconds ac(juires such a velocity as 

 enables it to reach the lake in the short s})ace of six minutes. The. 

 late Professor Piayfair, from whose works this notice is taken, saw. 

 five trees come down ; the greatest of them was a spruce fir a hun- 

 dred feet long, four feet in diameter at the lower end, and one foot 

 at the upper. The slide crosses in its way three great ravines, 

 one at the height of 64 feet, anotlier at the height of 103, and the 

 third, where it goes along the face of a rock, at that of 157 ; in two 

 places it is conveyed under ground. 



X. Preparation of Sulphurel of Mercury, 

 Dr. Taddei recommends the following process for the preparation of 

 this substance, as being one which effects the combination immediately, 

 and in a more perfect manner than that generally employed. Put one 

 part of sulphuret of potash into a mortar, with three or four parts of 

 mercury ; triturate together, adding a little water by degrees, until the 

 whole is reduced to a homogeneous black paste ; then add flowers of 

 sulphur, in equal quantity to the mercury employed, and mix the 

 whole by a short trituration. Then wash the sulphuret with repeated 

 portions of water till all the alcaline sulphuret is removed. The sul- 

 phuret thus prepared is not of the black colour of that obtained by 

 simple trituration. Dr. Taddei says, that the addition of a little sul- 

 phuret of potash to the mixture of sulphur and mercury, does not 

 render a long trituration unnecessary, but that, proceeding as above, 

 the substance is prepared instantly. — (Giornaie di Fisica, v. iv. p. 12.) 



Article XVI. 

 NEW SCIENTIFIC BOOKS 



JUST PUBU9HCD. 



The Use of the Blowpipe, in Chemical Analyses, and in the Exami- 

 nation of Minerals. By J. J. Berzelius, Member of the Academy of 

 Stockholm, &c. &c. and translated from the French of M. FVesnel, by 

 J.G. Children, FliS. L. and E. FLS. «&c. &c. With a Sketch of Ber- 

 zelius's System of Mineralogy ; a Synoptic Table of the principal 

 Characters of the Pure Earths and Metallic Oxides before the Blow- 

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 Three Plates. 8vo. 12^. 



Conversations on Mineralogy. With Plates, engraved by Mr. and 

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 Figures of Minerals, including 12 beautifully- coloured Specimens. 

 2Vols. 12mo. 145. Boards. 



An Inquiry into the Opinions, Ancient and Modern, on Lifie and 

 Organization. By John liarclay, MD. 8vo. 145. 



An Epitome of Pharmaceutical Chemistry, whereby the Artof pre-» 

 scribing scientifically may be facilitated. By Rees Price, MD 



