CAPTIVE MOLECULES 



with. The recognition of this fact constitutes one of 

 the three really important advances that have been 

 made in the steam engine since the time of Watt. The 

 other two advances consist of the utilization of steam 

 under high pressure, and of the introduction of the 

 principle of the compound engine. 



Neither of these ideas was unknown to Watt, since 

 the utilization of steam under high pressure was ad- 

 vocated by his contemporary, Trevi thick, while the 

 compound engine was invented by another contempo- 

 rary named Hornblower. Perhaps the very fact that 

 these rival inventors put forward the ideas in question 

 may have influenced Watt to antagonize them; in 

 particular since his firm came into legal conflict with 

 each of the other inventors. At any rate, Watt con- 

 tinued to the end of his life to be an ardent advocate of 

 low pressure for the steam engine, and his firm even 

 attempted to have laws passed making it illegal on the 

 ground of danger to human life to utilize high-pressure 

 steam, such as employed by Trevi thick. 



Possibly the conservatism of increasing age may also 

 have had its share in rendering Watt antagonistic to the 

 new ideas; for he was similarly antagonistic to the idea 

 of applying steam to the purposes of locomotion. Trev- 

 ithick, among others, had, as we shall see in due course, 

 made such application with astonishing success, pro- 

 ducing a steam automobile which traversed the highway 

 successfully. In his earlier years Watt had conceived 

 the same idea, and had openly expressed his opinion 

 that the steam engine might be used for this purpose. 

 But late in life he was so antipathetic to the idea that 



