My life : a record of events and opinions - Wallace-online.org

'70 MY LIFEAt the same time the canal had been improved atgreat cost to enable it to carry the increased tradethat had been caused by the rapid growth of Londonand the prosperity of agriculture during the earlyportion of the nineteenth century. About thirtymiles further on the watershed between the riverbasinsof the Ouse and Severn had to be crossed, adistrict of small rainfall and scanty streams, fromwhich the whole supply of the canal, both for its locksas well as for evaporation and leakage, had to bedrawn. Whenever there was a deficiency of waterhere to float the barges and fill the locks, trafific waschecked till the canal filled again ; and this hadbecome so serious that, for a considerable portion ofthe canal, it had been found necessary to erect steam-engines to pump up the water at every lock from thelower to the higher level. Sometimes there were two,three, or more locks close together, and in these casesa more powerful engine was erected to pump thewater the greater height. Up to this time I hadnever seen a steam-engine, and therefore took thegreatest interest in examining these both at rest andat work. They had been erected by the celebratedfirm of Boulton and Watt, and were all of the lowpressuretype then in use, with large cylinders, overheadbeam, and parallel motion, but each one havingitsspecial features, the purport of which was explainedto me by my brother, and gave me my first insightinto some of the more important applications of thesciences of mechanics and physics.Of course at that time nobody foresaw the rapiddevelopment of railways all over the country, orimagined that they could ever compete with canalsin carrying heavy goods. Yet within two years afterthe completion of the lineto Birmingham, the traffic