668 
Report on the Trials of Portable 
view, and what the circumstances under which the Society pro- 
posed, after so many years' intermission, to hold new trials of 
engines at Newcastle in 1887. 
In 1881, or nearly ten years after the Cardiff trials, Mr. Ander- 
son, Consulting Engineer to the Society, published an article 
on " Compound Engines for Agricultural Purposes " in the 
pages of the ' Journal,' with the professed object of laying 
before Agricultural Steam-users " the salient features and advan- 
tages of the Compound System in Steam-engines, and so to 
enlist their interest in the, probably, rapid adaptation of the 
principle to Agricultural Engines." 
Compound engines, at the time in question, were in course 
of displacing simple engines in the steam-ship, the factory, the 
mill, and the mine ; while their adoption for locomotive pur- 
poses was under consideration, Messrs. Fowler and Co. had, 
indeed, already shown a compound semi-portable engine at 
Kilburn in 1879, Messrs. Garrett, a portable compound at Car- 
lisle in 1880, while Fowler, Garrett, Burrell, and Aveling, had 
all followed suit at Derby in 1881, before the Society's Engineer 
undertook to advocate the use of compound engines in agri- 
cultural practice. 
Mr. Anderson began by showing that economy of fuel is 
impossible in the vast majority of portable engines, almost all 
of which have only a single slide-valve, and, consequently, a 
low rate of expansion. On the other hand, he pointed out that 
engines, fitted with expansion gear, automatic or other, are 
complicated in their details, and apt to get out of order, while 
the compound engine promises to effect all the saving of coal 
which characterises simple expansive engines with the use of 
simple valve gear. It was further argued that, although the 
compound system involved the use of a second cylinder, the 
boiler, having less steam to furnish, would become lighter, while, 
if the working pressure were increased to 120 or 150 lbs. per 
square inch, the compound agricultural engine of the future 
would probably weigh, and cost, little more than its spendthrift 
predecessor, 
Mr. Anderson's indictment of existing practice was too 
weighty, and his anticipations of the advantages to Jbe gained 
from a change of system too probable, to be without effect on 
the minds of the Council. In addition, it was patent that 
compound engines were fast superseding simple engines in the 
industrial world generally, while the portents of a coming 
change in agricultural practice were yearly becoming more 
numerous in the exhibits of the Royal Agricultural Showyard 
itself. 
Finally, waiving certain old prejudices against high-pressures, 
