Agricultural Stedrti-enyines at Newcastle. 
677 
gases, and in the measurement of the volume of air passing 
through the furnace. 
Each engine was really subjected to three independent 
trials : — 
(1.) A Preliminary Run, during which the time taken in raising steam 
I'rom cold water, first to 60 lbs., and then to the working pressure, 
was noted ; the exhibitor being, meanwhile, allowed to make any 
adjustments he pleased in his engine. These " Preliminary Runs," 
giving no data of importance, are not described in this Report. 
(2.) Tlie Trial Run, lasting four hours, or thereabouts ; and determining 
economy, on the brake ; and 
■■(3.) A Secondary Trial, during which each engine was indicated, the 
governor control tested, the smoke-box gases analysed, and the 
amount of air passing through the furnace measured. 
;# Powell's Duffryn coal was used on this occasion, the 
Llangennech Colliery, from which the Society has hitherto 
drawn its supplies for trials, being no longer in work. The 
Report on the Composition and Calorific Power of various Coals, 
forming a supplement to the Judges' Report of the Cardiff 
Engine Trials, places Powell's DufFryn coal ahead of all the 
Welsh steam coals for efficiency, and makes it slightly superior 
to Llangennech. 
Each competitor, as on previous occasions, provided his own 
fireman, who was unassisted in the management of the engine 
during the trial run. A " tachometer," attached to the brake, 
saved a good deal of counting, and enabled Engineers and Judges 
to see at a glance whether the engine under trial was keeping z 
regular speed. 
The leading dimensions of all the engines and boilers tried 
are given in the Tabular Statement of Results, prepared by the 
Society's Engineers, which accompanies their Report, and are 
therefore omitted from the general descriptions which follow, 
for the sake of avoiding needless repetitions. 
The Trial Runs. 
These commenced on Tuesday the 5th of July, the first 
engines got into position being those of the Alnwick Foundry 
Company and Messrs. Davey Paxman and Company, both of the 
Simple type. Of these, the latter made only a preliminary run 
on the day in question. 
Simple Portable Engine hy the Alnwick Foundry Company 
(No. 3111). — The exhibitor elected to run at a speed of 150 
revolutions, a pressure of 80 lbs., with a brake-load of 16 horse- 
power. 
This engine was understood to be a first essav on the part 
1 2 Y 2 
