a Neii) Steam-Efigine mtkoui a Boiler* S5 



yator> with a particular stop^cock, that when open, it shall cut 

 off the communication between the generator and the side 

 valves. Let this cistern be filled brimful with water, and the 

 cock at the bottom of the generator left open. If the cock of 

 the cistern be opened the whole water of the cistern will escape 

 through the generator ; and if the time it takes to escape be 

 observed by a pendulum or stop-second watch, the repetition 

 of this experiment at any time will show if the passage through 

 the generator be contracted since last experiment. Should it 

 be found to be so, it is then proposed to fill the generator with 

 diluted muriatic acid, taking care to cut off the communication 

 between it and the shde valves. After letting it remain in the 

 generator a sufficient time, it is then to be washed out with 

 warm water poured into the above-mentioned cistern. If the 

 cistern be filled brimful it will serve to ascertain if the pas- 

 sage be clear, by observing the time it takes to pass through 

 the generator. Repetitions of these experiments will undoubt- 

 edly free the generator of all calcareous matter. But as 

 none of the strong acids act on the crust formed by sea water, 

 it is therefore proposed to proceed in the same manner with 

 diluted sulphuric acid, taking care never to give time for much 

 crust to form by sea water, so that by the diluted sulphuric 

 acid partly acting on the iron, it shall effect the removing of 

 an imperfect crust produced from salt water ; the generator to 

 be always thoroughly washed out with warm water. 



The length of time that this engine has been in construct- 

 ing, gave ample time to devise improvements. Several were 

 proposed, but few of them were thought of in time to be intro- 

 duced without making material alterations on the parts made ; 

 such as improvements in the manner of constructing generators 

 of greater strength, but of which it is unnecessary to lengthen 

 this paper with a description. However, one thing may be 

 mentioned, as it would add to the improvement of the engine. 

 In place of working the escape steam slide valve by the im- 

 mediate action of the centrifugal balls, it was proposed that 

 the axis of a bevelled wheel should be turned by the ma- 

 chinery of the engine, and which is to turn other two bevelled 

 wheels on one axis. These two last mentioned wheels are neither 

 of them to be fixed to the axis, but both to slip round freely 



