TRANSACTIONS OF SECTION G. 881 



of Clarke's beautiful process, by the application of chemistry, water, owing- its hard- 

 ness to that common cause, carbonate of lime, is rendered as soft as the water from 

 the mountain lake. Taking- that other branch of engineering commonly coupled 

 with water, viz., the supply of gas, the engineer is helpless without the application 

 of chemistry. From the examination of the coal to be used, to the testing of the 

 gas to be supplied, there is not one stage where chemical science is not necessary. 

 The consumer requires gas which shall be as nearly as possible a pure hydro- 

 carbon of high illuminating power, and it might well have been that a person to 

 whom was delivered the crude gas as it issued from the retort would have said, 

 4 Certain things may be separated out more or less, but to practise on a whole- 

 sale scale the delicate operations which will be needed to cleanse the illuminating 

 gas from its multifarious accompanying impurities is a hopeless undertaking, 

 and must be so if for no other reason than this — the excessive cost that would be 

 entailed.' But what are the facts? Although I for one do not like to sit hi a room 

 where gas is burnt, unless special provision is made for taking away the products 

 ■of combustion, the engineer of the present day, thanks to the application of 

 chemical science, delivers gas to the consumer in a state of comparative purity 

 (although it may have been made from impure coal) which but a few years ago 

 would have been deemed impossible ; and so far is this improvement from being 

 attended with extra cost, that the residual products not now uncommonly all but 

 pay the whole cost of the coal, and in some rare instances even leave a slight profit 

 to go towards the charge for labour. Again, it is by the application of chemical 

 science in the dynamite and the gun-cotton of the present day that the engineer is 

 enabled to prepare submarine foundations, to blast away shoals, and to drive tunnels 

 through rock of a character that cannot be dealt with by mere cutting-machines. 

 Equally to the application of chemistry is it due that there are hopes, by the em- 

 ployment of lime cartridges, of breaking down coal without that risk of igniting fire- 

 damp which is attendant upon the use of gunpowder. I need hardly observe that 

 much more might most pertinently be said on the way in which the engineer 

 applies chemical science. In fact, those ways are so multifarious, that a volume 

 might be written upon them, but I must pass on and ask you to consider how the 

 ■engineer applies geological science, the science treated by Section C. 



I have already spoken of the engineer supplying towns by water collected from 

 the surface ; even he, however, must have a knowledge of geology, for without it 

 he will not know what places are apt for the huge reservoirs he constructs, nor 

 where he can in safety make his enormous embankments. In this continent of 

 vast lakes one feels it must excite a sensation of the ridiculous when a ' Welsh lake ' 

 is spoken of, but I must ask you to believe you are in Lilliput, and to imagine that 

 the ' Bala Pond ' of eleven hundred acres in extent is really ' Bala Lake,' as it is 

 called. Within a few miles of that, our friends at the other end of the Atlantic 

 steam ferry, the inhabitants of Liverpool, are now constructing, under the engineer- 

 ing and advice of Mr. Hawksley, waterworks which will involve the formation, 

 I believe one may safely say the re-formation, of a lake, practically the same area as 

 that of Bala, of some 80 feet in depth, and containing between the overflow and 

 the point of lowest discharge nearly twelve thousand million gallons. This lake 

 will be made by the throwing from side to side of the valley of a solid stone bank, 

 100 feet above the ground, 146 feet above the deepest part of the foundations, and 

 113 feet thick at its thickest part. Contrasted with Lake Superior this new 

 lake will be small, a thing even demanding a microscope, but the bursting 

 of the wall would liberate a body of water sufficient to carry death and ruin 

 throughout a considerable district. It is, therefore, in the highest degree im- 

 portant that whether he be constructing the solid stone wall, or the more 

 common earthen embankment with a puddle trench, the engineer should so 

 apply geological science as to ensure the safety of his work. But in those 

 cases where the waterworks engineer has to derive the supply from under- 

 ground sources, the application of this science is still more necessary ; he must 

 know whether he is likely to find a water-bearing stratum at all — if so, where 

 it receives the rain from heaven, and the extent of the area which receives it ; in 

 what direction the water travels through it, what is the varying height of water 

 1884. 3 l 



