The British Association. 
55 1 
1876.] 
mankind will be marked by alternate periods of adtivity and repose ; nor will 
it be the work of any one nation or of any one race. To the eredtion of the 
edifice of civilised life, as it now exists, all the higher races of the world have 
contributed ; and if the balance were accurately struck, the claims of Asia for 
her portion of the work would be immense, and those of Northern Africa not 
insignificant. Steam power has of late years produced greater changes than 
probably ever occurred before in so short a time. But the resources of Nature 
are not confined to steam, nor to the combustion of coal. The steady water- 
wheel and the rapid turbine are more perfect machines than the stationary 
steam-engine ; and glacier-fed rivers with natural reservoirs, if fully turned to 
account, would supply an unlimited and nearly constant source of power 
depending solely for its continuance upon solar heat. But no immediate dis- 
location of industry is to be feared, although the turbine is already at work on 
the Rhine and the Rhone. In the struggle to maintain their high position in 
science and its applications, the countrymen of Newton and Watt will have 
no ground for alarm so long as they hold fast to their old traditions, and 
remember that the greatest nations have fallen when they relaxed in those 
habits of intelligent and steady industry upon which all permanent success 
depends.” 
Two Evening Ledtures were delivered ; one by Prof. Tait, “ On Force,” and 
one by Sir Wyville Thomson, “On some Results of the Challenger Expe- 
dition.” In his ledture “ On Force” Prof. Tait observed that some criticisms on 
works in which he had at least had a share had shown him that even among the 
particularly well-educated class who wrote for the higher literary and scientific 
journals, there was widespread ignorance as to some of the most important 
elementary principles of physics. He had therefore chosen as the subjedt of 
a ledture a very elementary but much abused and misunderstood term, which 
met us at every turn in the study of natural philosophy. If one had a right 
to judge of the general standard of popular scientific knowledge from the 
statements made in the average newspaper, or even from those made in some 
of the most pretentious among so-called scientific ledtures, there could be but 
few people in this country who had an accurate knowledge of the proper sci- 
eentific meaning of the little word “ force.” We read constantly of the 
so-called “ Physical Forces” — heat, light, eledtricity, &c. ; of the “ Correla- 
tion of the Physical Forces of the “ Persistence or Conservation of Force.” 
To an accurate man of science all this was simply error and confusion, and he 
had full confidence that the inherent vitality of truth would render the attempt 
to force such confusion upon the non-scientific public quite as futile as the 
hopelessly ludicrous endeavour of the “Times” to make us spell the word 
‘ Chemistry ” with a “ y ” instead of an “ e.” There was no objedtion to such 
phrases as “ the force of habit,” “ the force of example,” &c. ; but when they 
read, as he had, in one newspaper, that the “ force ” of a projedlile from the 
81-ton gun had at last reached the extraordinary amount of 1450 feet, in ano- 
ther that the “force ” of a ball from the great Armstrong gun lately made for the 
Italian Government was expedted to average somewhere about 30,000 foot- 
tons, and in a third that the water in the boiler of the Thunderer “ would in a 
second of time generate force sufficient to raise 2000 tons 1 foot high,” they 
saw that there must be somewhere at least, if not everywhere, a most reckless 
abuse of lauguage. In fadt they had come to what ought to be scientific 
statements, and there even the slightest unnecessary vagueness was altogether 
intolerable. Perhaps no scientific English word had been so much abused as 
the word “ force.” We hear of “ Accelerating Force,” “ Moving Force,” 
“Centrifugal Force,” “Living Force,” “Projedlile Force,” “Centripetal 
Force,” and what not. Yet there was but one idea denoted by the word, and 
all force was of one kind, whether it was due to gravity, magnetism, or elec- 
tricity. This alone served to give a preliminary hint that there was probably 
no such thing as force at all, but that it was merely a convenient expression for 
a certain “ rate.” Much of the confusion about Force was due to Leibnitz 
and some of his associates and followers, who, whatever they may have been 
