656 TRANSACTIONS OF THE 



It is designed for stationary engines exclusively, and by using a weight 

 instead of a spring, is intended to avoid the inaccuracy ■which sometimeg 

 results from corrosion, wear, change of temperature, or other accidents to 

 which springs are liable. 



The weight is in the form of a pendulum, and operates on the principle 

 of the pendulum balance ; and it appears to your committee that it will 

 operate well, and truly indicate the pressure, and that if the parts which 

 are liable to get out of order should at any time fail, the indication will 

 still be correct, unless the derangement is so gfeat as to be discovered. 



Your committee therefore recommend the gauge as having an element 

 of safety that is wanting in gauges that are used for locomotive and marine 

 engines, and as being otherwise as simple and easy to construct as other 

 gauges that are in common use. 



J. K. FLSHEK, 

 W. H. BUTLER, 

 FRANK DIBBIN, 

 Co7nmit{ee. 



Jones Patrick's Variable Exhaust. 

 The committee respectfully report- 

 That they have examined the model submitted to them, and consider its 

 principles, and the necessity that exists for its use, and have compared it 

 with other devices for the same purpose. 



They are informed that there are comparatively few locomotives which 

 can make steam freely with wide blast orifices. Most engines use narrow 

 orifices, which cause back pressure, but do not need that the orifices should 

 be at all times so narrow. It therefore appears that such engines might 

 be benefited by a variable apparatus. 



In examining the variable exhausts in use, your committee find that none 

 are entirely free from objections. Some obstruct the steam by internal 

 cones, solid or hollow; others obstruct the smoke, by projections outside ; 

 others are defective in the mechanism by which they are changed. 



Mr. Patrick's may be made entirely free from internal obstruction. It 

 has an external obstruction, which, theoretically, i.s objectionable. The 

 nozzle should taper on the outside nearly to an edge, so as not to cause 

 eddies. The amount of this objection is not known by trial ; but your 

 committee believe it to be less than that of other forms. 



The mechanism by which Mr. Patrick changes the orifices appears to be 

 excellent, and your committee believe that the objection they have referred 

 to is on the whole less than the objections which lie against the other forms 

 of variable exhaust which they have seen. And they recommend it to 

 those who have engines that cannot do their heavy work with orifices of 

 liberal size. J. K. FISHER. 



FRANK DIBBIN, 

 W. H. BUTTLER, 



Committed 



