(334.) 
His Me- 
chanical 
Philosophy. 
872 
of taking part in the actual execution of scientific 
designs; of studying foreign languages; and of 
methodizing his knowledge for the purposes of in- 
struction. Every one of these influences may be 
clearly traced in his writings, which will challenge 
comparison with those of any English writer, exeept 
perhaps Dr Thomas Young, for variety and fulness 
of information, and for the general soundness and 
strongly practical character of the mechanical know- 
ledge with which they abound, They would also 
doubtless have appeared to far greater advantage had 
they been the product of his most vigorous days ; but 
he was little known as a writer until the year 1793, 
when he commenced a series of important contribu- 
tions to the Encyclopedia Britannica, embracing 
at least forty-six articles, all scientific, some of great 
length and elaboration, which were published during 
the succeeding eight years, a period when he was seri- 
ously afflicted with chronic disease. They embraced 
disquisitions on general philosophy, as in the articles 
Philosophy and Physics; of strict science, as in 
Astronomy, Dynamics, Projectiles, Pneumatics ; of 
the more experimental sciences, as in Magnetism, 
Electricity, Sound; of the art of music (with which 
he was practically conversant), in Temperament, 
Piano, &c.;—but his great strength lay in the ar- 
ticles in which just mechanical principles were ap- 
plied successfully, and often with marked originality, 
to practice, as in Arch, Roof, Carpentry, and Strength 
MATHEMATICAL AND PHYSICAL SCIENCE. 
[Diss. VI. 
who might have been called upon for a scientific 
opinion (of far more weight than what generally goes 
by the name) on almost any practical subject upon 
which he might have been consulted ; and that not 
merely in its general outlines, but in its strictest de- 
tails; not only the design for a roof or a centre, 
but the scantling of the timber to be used; the mi- 
nutiz of a pump or hot-air stove; the curvatures of 
an achromatic object-glass; the temperament of a 
piano ; or the angle for the pallets of an escapement. 
In such matters nothing important either in the 
theory or the practice of his times escaped him. His ~ 
opinions were very generally formed on original con- 
siderations, supported by experiments equally well 
devised and carried out. His method of finding 
mechanically the relation between the intrados and 
extrados of a properly balanced arch by means of 
suspended pieces of chain is as ingenious as it is 
elementary ; but his observations on the manner in 
which stone arches, when overloaded, break up, es- ~ 
tablished on direct observation and experiment, un- 
questionably gave a just foundation to the theory 
of masonry, till then so generally and erroneously 
treated of by mathematicians with the preposterous 
abstraction of the forces of friction and cohesion, 
the action of which in many instances vastly exceeds 
the direct effect of gravity. 
But on this we must not dwell.. Robison’s articles 
(335.) 
on Electricity and Magnetism are deserving of nearly Writings 
of Materials; Resistance, Rivers, and Waterworks; equal praise with reference to the state of knowledge ?* bees 4 
Seamanship, Steam and Steam-Engine; Machinery, of the time. Probably there was not one author of magaenaadl 
Telescope, and Watchwork. 
The last-named articles (most of which have been 
collected in a compilation, edited by Sir David 
Brewster, in four thick volumes, entitled Robi- 
son's Mechanical Philosophy) constitute a body 
of knowledge in civil engineering which has not 
yet been surpassed in clear exposition of physi- 
eal principles and their application—in the ex- 
tensive acquaintance it shows with the details of 
practice—and in proofs of elaborate and impar- 
tial study of authors, both British and foreign, on 
the subjects of which it treats. Several of these 
articles have been resorted to by the most accom- 
plished engineers of our own time as stores of sound 
experience, and they have been lavishly borrowed from 
by some writers on similar subjects, occasionally with- 
out acknowledgment. The original matter which 
they contain is not always easily separated from that 
which is compiled. In every instance Dr Robison 
merit on these subjects, whatever his country or lan- 
guage, whose works he had not laboriously consulted 
and analysed the conclusions; whilst a multitude of 
ingenious experiments give evidence of the skill and 
patience of the writer. To Dr Robison we are, indeed, 
indebted for the approximate knowledge of the pri- 
mary law of electric attractions and repulsions; for 
a careful consideration of those beautiful curves 
formed by iron filings round magnets,! to which such 
an enlarged importance has since been given by the 
beautiful generalizations of Mr Faraday; and I be- 
lieve likewise for the first suggestion of combining 
the voltaic elements in a pile or column,.? Dr Robi- 
son, though for many years secretary of the Royal 
Society of Edinburgh, published little in its Transae- 
tions, and almost nothing, so far as I am aware, in ~ 
any periodical work. Hence his admirable adapta- 
tions of experiments were little known beyond his 
own class and friendly circle. 
Of his more abstract mathematical writings we  (336.) 
need say little. He was thoroughly acquainted with His exten- 
the works and methods of Newton, and with nearly ple 
all those of the same school, particularly of Bos- mathe- 
covich. He laboured incessantly to reduce the de- matical ac- 
monstrations of the higher mechanics and astrono- sen 
lays claim to less than his own share, and is so 
scrupulous in quoting the names of other authors, 
that he has unquestionably received. less reputation 
from these Essays than he deserves, He writes like 
a man who has himself used the saw and hammer, 
who has had the responsibility of success or failure, 
Sound 
practical 
views. 
1 Indirectly we owe to him also the first exact determination of the mathematical. properties of these curves, made at his 
wie by Mr Playfair.—Robison’s Mech. Phil., iv. 350. 
See the Fifth Dissertation (by Sir John Leslie), p. 739. 
