CHEMICAL SCIENCE. 269 



the oxygenated part of bop-oil with nitric acid, the author was unable 

 to obtain anything more than a brittle yellow resin. A series of ex- 

 periments have also been made in regard to the physiological action 

 of hop oil. It does not appear to produce any narcotic effect, and 

 corresponds with other volatile oils. A rabbit bore a dose of 20 drops 

 without loss of appetite or any other sign of discomfort. 



Rochleder's investigations have shown that the so-called active 

 principles are common to all the members of a natural family. Both 

 hops and hemp belong to the Urticacese ; both plants have a great 

 analogy in a physiological point of view. Now since the narcotic 

 effect of beer results from a yet unknown constituent of the hop, prob- 

 ably an organic base, and as hemp, according to the above principle, 

 would contain the same constituent, it would perhaps be theoreti- 

 cally correct to grow hemp instead of hops for the purpose of 

 communicating to beer its bitter taste and narcotic properties. The 

 bitter of hemp closely resembles that of the hop. In an agricultural 

 point of view this would be very advantageous, for besides the fact 

 that the growth of hemp is less dependent than the hop upon meteo- 

 rological conditions, the former can, after the extraction of the soluble 

 constituents, be employed in making yarn. 



ANALYSIS OF OILS BY SULPHURIC ACID. 



The fishy oils mixed with sulphuric acid set free from heat ; this 

 action serves to distinguish them, and to separate decidedly, the dry- 

 ing oils from the others. 



In a common tumbler place 50 grammes of olive oil, place a ther- 

 mometer in the liquid to ascertain the temperature, pour upon it 10 

 cubic centimetres of concentrated sulphuric acid (66 Baume) ; mix 

 the liquids by agitating with the thermometer, and observe the rise of 

 temperature. If the temperature of the oil and acid at the commence- 

 ment is 25 C., the thermometer will indicate presently 67 C., being 

 an increase of 42 C. The mixture does not require more than two 

 minutes to arrive at the maximum temperature. 



In another glass place 50 grammes of poppy oil, and treat it in like 

 manner with the acid ; if the temperature at the commencement is 

 26 C., the thermometer will rise to 100. 5C. showing an increase of 

 74.5 C. 



It is essential to remark in this case, 1st, a considerable disenorao-e- 

 ment of sulphurous acid, which is not produced by the olive oil ; and, 

 2d, a bubbling or boiling up of the liquid ; in consequence of these two 

 circumstances, the number 74. 5 is somewhat uncertain. 



The difference between 42 and 74.o is so great, that it gives us 

 the means of analysis. 



The experiment repeated many times under the same conditions, 

 with the same olive oil, always gives the same development of heat, 

 42. The experiment made with olive oil from different provinces, 

 shows that the action of the sulphuric acid is constant when the oil is 

 pure, always producing the same degree of heat. 



