938 Tbaxsactioxs of the Americax Ixstitute. 



Thomas D. Stetson, Esq., the enf^jioeer in charge of these tests, then, 

 and ever since, an active member of the Institute and its Poly technic 

 branch. We reproduce below that portion of two of his letters 

 relating to the test, with the original running heading, combining 

 both letters into one and omitting most of the prefatory matter : 



Importance of and DifBculties Attending Practical Tests at Fairs — The Tests of 

 Stationary Non-condensing Steam Engines at the Crj-stal Palace — The Programme 

 — Methods Finally Adopted — Use and Abuse of the Expansive Principle in Steam 

 Engines — Its Operation in these Engines — Effects of Friction on the Benefits of 

 Expansive Working — Per Centage of the Heat actually Converted into Mechani- 

 cal Eifect — Fluctuations in Speed under Uniform Loads — Ditto under very Vari- 

 able Loads — Table of Results relating to Economy — Table of Results relating to 

 Regulation — Method of Recording Circumstances — Method of Changing Load. 



When a movement was made by one of the exhibitors to procure 

 a practical test of fireproof safes, each exhibitor declared himself 

 anxious for such a trial, but each must, it appeared, be allowed to 

 prescribe the conditions. One would allow each to manufiicture a 

 safe of a certain size, thickness, &c., for the especial purpose; another 

 must allow each to make his safe in such style and dimensions as he 

 saw tit; a third would have a committee appointed to select one safe 

 made by each from those already sold and in use ; a fourth would 

 allow the manufacturers to designate a certain number, say five or 

 ten such, from which the committee would choose ; .a fifth, distrust- 

 ing the ability or the honor of the committee, would allow each party 

 to choose for themselves among the safes already sold by them and in 

 use ; while a sixth woiild test no other than the safes entered for exhi- 

 bition. The evident impropriety of sacrificing the elegantly- wrought 

 structures prepared merely for exhibition, afibrded most of the exhi- 

 bitors a quite reasonable excuse for declining to enter the competition 

 on the basis last named. 



There are almost invariabl}^ good objections to every programme 

 that can be made for such a purpose ; but if, as the published reports 

 and addresses assure us, all the exhibitions are yearly becoming more 

 interesting and beneficial, the making of practical tests, rather than 

 superficial surveys of com])eting articles, should be distinctly recog- 

 nised ; and there is no journal more proper than yours in which to 

 enunciate the proposition, as the next step to be taken in any really 

 "great" industrial exposition. Let the tests be public, and as 

 thorough as practicable. If the world is not prepai-ed — if, in other 

 words, it is not yet practicable to make any such tests, let it be under- 

 stood simply that this is the direction in which true progress will be 



