Cuir. IV., § 2.] 
my to their simplest and most geometrical elements. 
But the result (as might have been foreseen) was in 
many cases a wearisome prolixity; and originality 
could not be expected in these departments without 
applying the continental improvements in analysis : 
not that Dr Robison overlooked these ; but he took 
little pleasure in them ; and as regards Physical As- 
tronomy he adhered to the older methods, Having 
been so long at St Petersburg, the writings of Euler 
must have been familiar to him, as indeed they evi- 
MECHANICS.—ROBISON—COULOMB. 
873 
elaborate statement of reasons, nor ever sullied by the 
suggestions of jealousy or self-conceit. Had he been 
an accomplished analyst he must have been less dis- 
tinguished in the equally important walk in which 
he stood pre-eminent. The limits of human life and 
faculties prevents universal attainment, but he was 
surely no mean philosopher of whom the sexage- 
narian James Watt could say, “He was a man of 
the clearest head and the most science of anybody I 
have known.” * 
dently were as far as regards all subjects connected 
with mechanics: he justly, however, considered Euler 
as a superficial natural philosopher, though an in- 
comparable mathematician. 
Amongst the contemporaries of Robison was one _ (339.) 
whose acquirements were in many respects very si- pepe 
milar to his own, and who contributed, in a degree ang passive 
second to no other philosopher of his day, to pro- strength. 
(337.) 
As a lecturer in his own department, Robison was 
Robison as the most eminent of his time, at least in Britain. That 
a lecturer, 
338.) 
His philo- 
sophical 
character, 
* his courses were not considered popular will easily be 
understood from a slight inspection of his writings. 
The demonstrations were long and copious, but too 
rapidly delivered, “The singular felicity of his 
own apprehension,” says Mr Playfair, made him 
judge too favourably of the same power in others.” 
The lectures must have abounded in practical details, 
which ordinary students rarely appreciate ; and they 
were deficient in experiments, which unquestionably 
arose from no want of the ingenuity necessary either 
to invent or execute them. On the other hand, the 
effect of his discourses was greatly enhanced by 
his striking and energetic delivery, and by the stores 
of his memory, which often recalled the incidents of 
the stirring life in which he had once been engaged ; 
and to the more thoughtful and philosophic they 
were rendered at once attractive and elevating in no 
ordinary degree by the strain of fervent thought by 
which they were accompanied, and the impress which 
they frequently bore of the pure morality and ex- 
alted piety of their author.! 
Apart from his local usefulness as a professor, we 
regard Dr Robison’s place in science as eminent 
chiefly on account of the sagacity with which he ap- 
plied knowledge to practice, and analysed complicated 
effects of force as manifested in engineering con- 
structions. This he did so ably as to guide future 
practice, and to reflect much light on the theory of 
solids more or less elastic and tenacious, and subject 
to the intricate strains which gravity produces. The 
difficulty and merit of these investigations will best 
mote sound views in the very same branches of 
science. Cuartes-Auaustin Coutoms (born 1736, 
died 1806) was, like Robison, addicted through life 
to practical enquiries, and was intimately acquainted 
with all the details of the civil engineering of his 
day. To him we owe a correct knowledge of the 
laws of friction in most ordinary cases, and the right 
application of them to the theory of machines, and 
to that of the stability of structures. In a very re- 
markable paper, published in 1776, he analysed, from 
the basis both of theory and experiment, the manner 
in which columns of masonry give way under longi- 
tudinal pressure; not, as had previously been sup- 
posed, by flexure under the imposed weight, like a 
steel spring or a rod of deal, but by the sliding of 
one portion of the column over another, at an angle 
determined by the cohesion of the stone, and capable 
of being reduced to a problem of maxima and mi- 
nima. This important principle is now known to 
apply to wrought and cast iron, and many other sub- 
stances. 
One of Coulomb’s happiest investigations was on _ (340.) 
the force of torsion, or the resistance of wires to 2 torsion. 
twisting ; which he showed to vary directly with the 
angle of torsion, inversely as the length of the wire, 
and directly as the square of its section. These me- 
chanical principles he applied with address to deter- 
mine the viscosity of fluids, and with still more con- 
summate skill and success to the measurement of 
electrical and magnetical forces by the construction 
of a Torsion Balance, similar in principle but ante- 
rior to that employed by Michell and Cavendish for 
estimating the force of gravity. 
be gathered from the slow progress of his successors 
in the same field. The criticism with which his 
writings abound on the theories of even his more 
celebrated contemporaries and predecessors show re- 
markable acuteness, patience, and independence of 
thought, We may perhaps sometimes think him pre- 
judiced, but his decisions are never uttered without an 
Coulomb's researches on electricity (which have (341.) 
been only partially published) will be made the sub- His r- 
ject of discussion in another chapter of this Disser-fessmpiea 
tation; they were the most sustained and elaborate Robison’s. 
of his investigations, and display very considerable 
mathematical resources. In this respect he had a 
superiority over Robison, who, as we have seen, cul- 
_- 
1 See Dr Chalmers’ Life, vol. i. That great man hada peculiar veneration for Dr Robison, and is understood to have received 
impressions from attending his lectures which materially influenced his future life. 
Mechanical Inventions of James Watt, ii., p. 290. 
VOL. I. 5s 
