TRANSACTIONS OP THE SECTIONS. 23 



charged its contents, on withdrawing a wooden pin from the beak, into 

 a glass goblet placed beneath, alongside of which a chronometer was 

 placed to indicate, in seconds, the time of efflux. The volume of liquid 

 used in each case was the same, — viz. 2,000 grain-measures, at 65° Fahr. 

 The times of efflux with liquids of the same specific gravity and bulk, 

 in the same vessel, vary with the viscidity of the liquids, and serve to 

 measure it. A correction ought to be introduced in estimating the 

 times of efflux of hot liquids, on account of the enlargement, by 

 expansion, of the bore of the glass tube ; but this, being a point of 

 little consequence in the practical application of this inquiry, has been 

 neglected. 



2,000 grain-measures of water, at 60° Fahr., ran off in 14 sec. 

 68 13 



164 12. 



When the funnel and glass tube were faintly smeared with oil, though 

 perfectly pervious, and apparently clean, boiling hot water having been 

 run through them, 



2,000 grain-measures of water, at 150° Fahr., ran offin24 sec. 

 142 23 



94 24 



56 25. 



So great is the repulsive influence between oil and water, in retarding 

 the flow of the latter through a small orifice. 



2,000 grain-measures of Fahr. Spec. grav. Sec. 



Oil of turpentine 65^^ 



Pyroxylic spirit ,, 



Alcohol „ 



Nitric acid „ 



Sulphuric acid ,, 



Ditto 262 



Saturated solution of sea salt 65 



Sperm oil ,, 



Fine rape-seed oil ,, 



Fine pale seal oil ,, 



Fine South Sea whale oil ,, 



Sperm oil 254 



Rape-seed oil 254 



South Sea oil 250 



The rape-seed oil is so viscid, as to burn with difficulty in lamps of the 

 ordinary construction, but in the hot oil lamp of Parker it affords a 

 very vivid light. In my former apparatus, the difference of level be- 

 tween the two legs of the siphon, which constituted the effective pres- 

 sure of efflux, was only half an inch, whereby 2,000 grain-measures of 

 sperm oil, at 64°, took no less than 2,700 seconds to run off, while that 

 volume of oil of turpentine ran off in 95 seconds. It would therefore 

 appear that the fluency of a viscid oil diminishes in a very rapid ratio 

 with the diminution of pressure. Hence, an oil will burn well in a 

 mechanical lamp, where it is raised to the level of the bottom of the 



' 0-874 ... 



.... 14 



0-830 ... 



.... 14i 



0-830 ... 



.... 16 



1-340 ... 



.... 131 



1-840 ... 



.... 21 





... 15 



1-200 ... 



... 13 



0-890 ... 



... 4.5i 



0-920 ... 



...100 



0-925 ... 



.... 66 



0920 ... 



.... 66 





.... 15 







... 17 





.... 17 



