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Scientific Intelligence. 



time, by creeping up between the mercury and the glass, and that it will 

 insinuate itself between any fluid and any solid, when it has not attraction 

 enough for the former to cause it to wet it. If any gas be confined in a glass 

 jar for a length of time over mercury, it will make its escape, and its place be 

 occupied by atmospheric air ; whereas the same gas, if confined by water, 

 will be preserved unmixed. Hence the best made barometers are often 

 studded with air bubbles. The cure which Mr Daniell has provided for 

 these evils is to weld a narrow ring of platinum to the open end of the 

 tube, which is immersed in the cistern. Boiling mercury amalgamates it- 

 self with platinum, and adheres to it when cold, wetting it, but not dis- 

 solving it, so that, by this means, the passage of the air is cut off as effec- 

 tually as if the whole tube were wetted by it. — Shumacher's Aslron. Nach- 

 richten, No. 73, p. 15. 



16. Hygrometr ic Properties of insoluble Compounds. — The following re- 

 sults were obtained by Mr T. Griffiths. The bodies, after being accurately 

 weighed, were exposed for a month to a moist atmosphere, and then 

 weighed. The increase is given in the following table, which we have ar- 

 ranged in the order of their absorptive powers : 



Oxide of zinc, - 29.0 



Foolscap paper, - - 18.0 



Charcoal from VVilmot, - 1 7-3 



Cartridge paper, - 17-1 



Sulphate of lime, - 16.2 



Charcoal tulip wood, - 15.4 



ash, - - 15.3 



Brown paper, - - 15.3 



Charcoal, Botany Bay wood, 15.2 



. lance wood, - 13.7 



— — — — cedar, - - 13.4 



— — — — American pine, 12.6 



— — — willow, - 12.1 



birch, - 12.0 



. . rose wood, - 12.0 



lime tree, - 11.8 



India paper, - - 11.6 



Charcoal, king wood, - 11.5 



Oxide of chrome, - 10.0 



Charcoal, zebra wood, - 6.6 



Serpentine, - - 5.2 



Filtering paper, - 5.0 



Plumbago, - - 4.5 



Oxide of iron, calc spar, 3.1 



■ '- manganese, black, 2.5 



Cornish clay, - - 2.4 



Smalt, - - 2.1 



Submuriate of copper, - 1.8 



Oxide oflead, litharge, - '1.7 



Mica slate, - - 1.1 



Drawing slate, - 1.0 



Sulphate of antimony, lime, .9 



Carbonate of lime, chalk, - .8 



Oxide of bismuth, - .7 



Tartrate of lead, - - .7 



Chloride of silver, - .6 



Carbonate of lead, - .6 



Oxide of iron, soda, - .5 



Chloride of lead, - .5 



Chromate of lead, - .5 



Phosphate of lead, - .5 



Carbonate of zinc, - .6 



Clay ironstone, - - .6 



Sulphate of lead, . .4 



Sulphuret of antimony, black, .4 



mercury, cinnabar, .4 



Fluor spar, blue, - .4 



Sulphate of baryta, - .3 



Zeolite, - - .3 



Oxide of lead, red, - .2 



mercury by nitric acid, .2 



Bisulphuret of iron, . .2 



Carbonate of baryta nat. - .2 



Aurum musivum, - .2 



Granite, - - .2 



Silica, powdered quartz, . .2 



Oxide of copper, black, - ,1 



— — — tin, putty, - .1 



Chromate of mercury, - . 1 



Sulphate of strontia, - .1 



Carbonate of strontia, - .1 



Joitrn. Roy. Inst. vol. xix. p. 93. 



