Pièce 222 - Letter from Peter Barlow

4 pp.

Woolwich - PB endeavours to answer some of WW's questions relating to steam trains. For instance, 'the effect of slopes upon the velocity of engines "as observed in real practice without reference to any theory". Most - if not all - engineers think that the rapid descent of a train does 'more mischief' that the heavy strain in the ascent. Some engineers assert that the more rapid the speed of a train, the more sharp is the draft. Consequently more fuel is consumed and hence more steam is generated in a given time, which leads to the more rapid destruction of the furnace and boiler. PB found no justification for this assertion in his research done on the Manchester line. The problem with trying to ascertain experimental facts is that 'they are so much at variance with each other that no instant conclusion can be obtained'.