352 



continues silent, the bar or dot is quite invisible ; but, as soon as 

 the sound commences, the black disc becomes diversified by a 

 series of whitish images of one or other of these objects arranged 

 at equal intervals around the central point. It is scarcely nec- 

 essary to say, that the number of these images, as well as their 

 apparent motion or rest, will depend on the time of rotation, as 

 compared with the intervals of the explosions of the flame. 

 Should it happen that the period of one revolution of the wheel 

 is precisely that of a certain number of the explosions, neither 

 more nor less, or that of, any multiple or sub-multiple of this 

 numbei", the images of the bar or dot will continue in each suc- 

 cessive rotation to present themselves at the same points ; but, 

 should this relation not subsist, these images will be seen to shift 

 their places on the disc, sometimes appearing to advance, and at 

 others to retreat. 



At the request of Mr. Bouv6, Dr. A. A. Hayes repeated 

 briefly, " An account of the present state of chemical 

 knowledge in relation to alcoholic beverages and their 

 falsifications," prepared for another Society. 



He stated that the products of fermentation, whether resulting 

 from " worts," in which the altered starch of grains furnishes the 

 material, or the " must," of expressed juices of grapes, fruits, 

 and plants, might be for convenience classed as Wines. 



Thus ale, which is the product of the first fermentation of 

 malted barley, may be considered the wine of malt ; the addition 

 of hop extract, being a matter of taste, which replaces the fruit 

 extract in wines. If we include also the mixtures of cane prod- 

 ucts, sugar and water, honey and water, and finally skimmed 

 milk, we have the sources of various resorts for producing exhila- 

 ration or intoxication, adopted by all nations. 



The first chemical change in many of the mixtures used is 

 produced by the remarkable body called diastase, which has the 

 power of converting nearly two thousand times its own weight 

 of starch into dextrine, or about half that quantity into grape 

 sugar. This body is developed in the act of germination in 

 grains and seeds ; and probably in this principle of malted barley 

 we have the type of a class of these substances, which, in differ- 



