8 



of 80 to 100 feet per second, while light travels 200,000 miles a 

 second. 



Saccharine, or to give it its due title of "Benzoilsulphonicionide," 

 was at first hailed as likely to be of great use in many departments 

 as a powerful sweetening agent, but many tests have proved that 

 there is little chance of its driving the sugar industry from the field 

 as a regular article of diet. It is prepared from one of the consti- 

 tuents of coal tar, and though in no sense a sugar, it possesses 

 immense sweetening properties, one grain being sufficient to sweeten 

 70,000 grains of water. It undergoes no change and does not 

 ferment in the system, and is therefore invaluable in some cases of 

 disease; it may also be used to disguise some noxious drugs, having 

 a distinct flavour of its own. It can also be used with advantage 

 in making jam, from its absence of fermenting properties ; jam 

 which has been prepared with saccharine is perfectly free from 

 fermentation, though exposed to intense heat, months after its 

 manufacture. On the other hand it has not so agreeable a flavour 

 as fruit sweetened by sugar. Moreover it will never be used for 

 confectionery, from which the maker derives his profit by weight ; 

 the quantity and weight of saccharine used in a given quantity of 

 sweetmeats being infinitesimal, whereas the cost has been even 

 greater than that of sugar. One can hardly wish that such a vast 

 field of industry as that of sugar cultivation should be abolished in 

 favour of a substance produced in the laboratory ; it would entail 

 terrible loss on thousands of all classes. Lastly the profession to 

 which I have the honour to belong is by no means unanimous as to 

 the benefit of exchanging a nutritive article of diet like sugar, for 

 one which passes unchanged through the body, excepting, as I have 

 said, in some cases of disease. 



Another manufacture of possibly great commercial value, is that 

 of artificial silk. M. de Cliardonnet has produced this by various 

 chemical solutions filtered and forced by pressure through a fine 

 tubular orifice, and which issue as a semi-solid thread, which, 

 when solidified by the air, may be wound like the silk from a cocoon. 

 The thread is supple, transparent, and silky; it is grey, or black, 

 but can be died. Cotton or other materials covered with a film of 

 this artificial silk, may serve as the basis of beautiful fabrics. I 

 must not leave this part of my address, which will specially interest 

 the feminine portion of my audience, without paying a tribute to 

 their infallible instinct with regard to scientific matters. Sydney 

 Smith defined a woman as " a biped who refused to reason, and 

 who lit a fire from the top." It is, hoM^ever, conclusively proved 

 that the scientific method of preventing smoke, and economismg 

 fuel when lighting a fire, is by doing so from the top. In this way 

 the hydro-carbon vapours from the coal pass through the fire above, 



