Popular Science Lectures. 165 
chemist thought that Coal Tar might yield a cheap 
substitute for quinine, and in his endeavours to find it, 
he stumbled on aniline dyes, a discovery which brought 
him at the outset £30,000. Still later, it has yielded that 
wonderful artificial sugar which it was feared would 
supersede the Cane product, and so cause Sugar planta- 
tions to become howling wildernesses. 
One of the most useful discoveries is that of anaesthetics, 
of which Chloral and Chloroform are the best known 
types. By these, suffering is prevented or at least allayed, 
and they are a boon to both patient and operator. 
Chemical means of producing extreme cold have been 
utilized so that ice can be produced in the tropics for 
less than it can be imported, and this artifical freezing 
has been largely used in conveying immense supplies of 
meat and of fruit from the Antipodes to the English 
Markets. We in British Guiana must hope that in the 
development of a fruit trade for which the colony has 
such abundant material and is so admirably adapted, 
these means of preserving in transit our more tender 
fruits will be found practicable and of value. 
Chemical inventions have also superseded the one 
explosive of former days, gun powder, by gun cotton. I 
remember as a school boy how we all went in for manu- 
facturing this delightfully dangerous compound, and how 
one impatient lad hastened the process by drying the 
produ6l of his experiment in the oven, the result being 
sending the oven door into the middle of the kitchen, and 
the cook into hysterics. Other explosives have also for 
certain purposes supplanted gun cotton — nitro-glycerine, 
dynamite and other similar compounds being extensively 
used in mining as well as for other less innocent purposes. 
