IS18.3 Scientific Intelligence. 231 



the date of the experiment ; secondly, the temperature of the 

 fluid employed ; thirdly, its density ; and fourthly, the time in 

 which a given quantity of it flowed through the tube. Some of the 

 principal facts which M. Girard ascertained were as follows : the 

 jate of the flow of pure water is four times as great at the tem- 

 perature of 194° (Fahr.) as at 32°; the rate of the flow of 

 alcohol is not so rapid, although it is considered to be more 

 perfectly fluid than water : this depends upon a greater attrac- 

 tion which glass possesses for alcohol than for water, from 

 which circumstance it follows that there is a stratum of the 

 alcohol in the interior part of the tube, which is thicker than 

 that formed by water, and proportionally obstructs the passage. 

 A solution of sugar in water, although much more viscid than 

 alcohol, flows out more rapidly ; but, in general, all these differ- 

 ences are less as the temperatures become more elevated. 

 M. Girard performed a series of experiments upon an aqueous 

 solution of nitrate of potash ; he found that the rate of its flow 

 was less rapid than that of water, except at high temperatures, 

 when they became more nearly the same. 



Some other circumstance, besides viscidity and temperature, 

 appears to affect the results ; if we introduce a thread into the 

 mouth of a capillary tube, through which the fluid escapes 

 only in drops, the flow becomes a continued stream, although, 

 in the two cases, the quantity of fluid discharged in the same 

 time is equal. It was found that the effect of temperature upon 

 the rate of the flow diminishes as we increase the diameter of the 

 bore of the tube. 



By comparing together the results of all the experiments, we 

 arrive at the general principle ; that when we employ the same 

 fluid, the time in which the same quantity flows out is in the 

 direct ratio of the temperatures and the inverse ratio of the cube 

 of the diameter of the tube. We may represent it by a geometric 

 curve, of which the abcisses will indicate the degrees of the 

 thermometer, and the ordinates the times necessary for the flow 

 of the same bulk of fluid. With respect to the comparative rate 

 of the flow of different fluids, it depends upon the affinity 

 between the tube and the different fluids, with which we are yet 

 only imperfectly acquainted. 



VII. Analysis of the Chenopodium Olidum. By MM. Chevalier 



and Lasseigne.* 



We are informed by these chemists that the analysis of this 

 plant offers some very remarkable results, of which the most 

 singular is that it contains a quantity of uncombined ammonia. 

 Tins is supposed to be the vehicle of the remarkably nauseous 

 odour which it exhales, strongly resembling that of putrid fish. 



When the plant is bruised with water, the liquor expressed, 

 and afterwards distilled, we procure a fluid which contains the 



• Abridged from Journ. Pliarm. iii. 412. (Sept. 1817.) 



