NATURE . 
[May 22, 1902 
fete) 
a 
0/000 
Naphthalinitoro-usesusstecs a dense eres 3200 
Chloral hy drate 1482 
Urea), 2. eeneecere 1579 
Tod oform>. 252. <<.sccrsessessts<s 2930 
Iodine .... 2510 
Sulphur cet eecmcceese treaczeseee nema 1152 
Mercury... Oda cx oto 0887 
Stole het aconngsnocen, sannanee, Gases sae 1865 
Graphite (Cumberland) ....................+ 0733 
Sodium, extending down to low temperatures, has a coeffi- 
cient about the same as that of mercury at the ordinary 
temperature. The coefficient for sulphur is about half of that 
between 0° and 100°, being 00002237, and that of iodine is not 
far removed from the value 0'000285 given for the solid at 
ordinary temperatures. The rate of expansion of liquid iodine 
is about three times this value. Paraffin ought to have a value 
of 0'0004633 from Fizeau, but Rodwell’s coefficient between 
o° and 38° is 000035. The value found for naphthalin is about 
half that of the liquid near its melting point, viz. 0'°000785. If 
the liquid coefficient be taken at a corresponding temperature to 
that of the liquid carbonic acid when comparing it with the 
solid, then its value is 0°001213, or the coefficient would be now 
in the ratio of 4 to 1. The graphite calculated from Fizeau 
should be 0’0000929, which is greater than my value; but the 
samples were different. My two specimens of chloride of am- 
monium gave nearly the same value, and the result is in agree- 
ment with that found by Playfair and Joule, viz. o‘ooo1gr. If 
a Fizeau coefficient for this salt is calculated, the value is 
00000761, which in this case is far too small. The coefficient 
found for oxalic acid is again only a little smaller than that 
given by Playfair and Joule, viz. 00002748. As regards the 
hydrated salts, phosphate of soda, hyposulphate of soda and 
chloride of calcium, having the respective values 0’0001384, 
00001516 and 00006887, as found by Kopp, the low tem- 
perature coefficients are much smaller in each case. With 
the exception of carbonate of soda and chrome alum, all the 
other hydrated salts have a coefficient of expansion not differing 
greatly from that of ice at low temperatures. Generally, the 
densities of the compressed blocks of different bodies agreed 
well with the results of other observers, but my potash alum had 
only a density of 1°614, whereas Playfair and Joule give 1°73T. 
It will be noted that iodoform is a highly expansive body like 
iodine, and that oxalate of methyl has nearly as great a co- 
efficient as paraffin, which is one of the most expansive solids. 
The correcting factor was used for paraffin, naphthalin, chloral 
hydrate, iodoform and sodium. 
It will be possible by cooling the moulds with liquid air during 
the process of hydraulic compression to produce cylindrical 
blocks of solid bodies of lower melting-points than any given 
in this investigation, such as alcohol, ether, nitrous oxide, 
ammonia, chlorine, &c., and” to ascertain their coefficients of 
expansion in the solid state between the individual melting 
points and the boiling point of liquid air. 
This method, which works well with liquid oxygen or air, 
fails when applied to liquid hydrogen, as the density of the 
liquid is too small (apart from other difficulties) to give accurate 
values of the weights of fluid displaced. For temperatures 
about 20° absolute, recourse must be had to measurements of 
the coefficient of linear expansion, and such observations could 
only be applied with ease to metallic bodies and alloys. 
THE RISE OF THE EXPERIMENTAL 
SCIENCES IN OXFORDS 
IX the Middle Ages, the scholars swept in flocks, like migrating 
birds, from school to school. What we now call a Uni- 
versity was then no particular spot on the earth ; but, like the 
ark in the wilderness, moved whithersoever a great teacher, such 
as Fulbert, the Anselms, Abélard, Peter Lombard, unfurled his 
standard. This mobility was, indeed, a guarantee of the free- 
dom and the power of learning. 
The ‘‘ Civitas Philosophorum,” as Saint Thomas called Paris, 
was engaged in 1209 in burning all the works imputed to Atis- 
totle. This attack ‘‘on the Lehrfreiheit” of Paris, when the 
culture of the first renascence was streaming into Europe from 
1 Abstract of the Boyle Lecture delivered at Oxford on May 13 by Prof 
T. Clifford Allbutt, F.R.S. 
NO. 1699, VOL. 66] 
the Arabian sources, drove its scholars abroad, and flights of 
them came to the comparatively unknown schools of Oxford and 
Cambridge. Oxford, already a centre of public affairs, sprang 
more suddenly than Cambridge into fame—on the scholastic 
side under the influence of the Friars Minors. 
The Grey Friars, then breathing the humane spirit of their 
founder, stood for the people and for freedom, while the Friars 
Preachers were on the side of authority. Robert Grosseteste, 
who made Oxford as Abélard made Paris and Fulbert made 
Chartres, and his pupils, Adam Marsh and Roger Bacon, became 
Greek scholars of no inconsiderable attainment at a time when 
the potable gold of Greek tradition had virtually died out in 
the west, and with it the inspiration of natural knowledge. 
Adam Marsh, himself a Minor, was a statesman, a close friend 
of Simon of Montfort, and a champion of freedom of learning. 
Balliol was founded under Franciscan influences, and under this 
first temper in the next century, then in the teeth of the Minor- 
ites, Oxford was keenly Lollard; and with the suppression of 
Lollardism all intellectual life deserted her courts. Neverthe- 
less, Oxford during the Middle Ages was a child of Paris rather 
than of Italy, whence Cambridge drew much of her nourish- 
ment, and was the picturesque stronghold of hierarchical 
traditions. Albert of Cologne, himself a Franciscan, vindicated 
against Paris the science of the Arab schools, and dignified the 
study of natural knowledge and experiment. 
Pioneers of science may be divided into two kinds, into a group 
who, like Galileo, Boyle and Harvey, were themselves discoverers, 
and a second group, like Roger Bacon, Telesio, Patrizzi, Campa- 
nella, Francis Bacon, Ramus and Marsiglio, who did service rather 
as protestants and reformers of method. Whether Roger Bacon 
were more of a chemist than Albert of Cologne, or whether 
either got beyond the chemistry of Geber, whether Bacon 
advanced in optics, his special study, beyond Al Hazen, it is 
less important to ascertain than to declare that Bacon’s title to 
fame is that he revived true methods of investigation. Many 
ancients had made experiments; Aristotle made many, Pliny 
made many ; Bacon first declared that it was not experiment, 
but the experimental method, which was to regenerate science. 
We must not suppose that Roger Bacon was alone, as one 
crying in the desert ; with the Arab illumination, natural science 
was inthe air. Many voices, such as that of Peter of Méricourt, 
to whom Bacon regarded himself as indebted, preached experi- 
ment and contemned authority in natural research. The works 
of Nemorarius of Borgentreich, who first advanced from the 
statics of Greek and Arab to dynamics, were known to Bacon. 
The parabolic mirror and its focus were known to Al Hazen. 
Grosseteste had larger views than either Hales or Albert, and 
was no inconsiderable geometer. He wrote a treatise, ‘‘de 
Iride et de Cometis,” and was a keen inquirer into the new 
sources of knowledge, including the ‘*Res Physica,” or 
medicine. Thomas Bungay, the eighth Provincial of the Friars 
Minors, was engaged with Bacon at Oxford in natural investi- 
gation, and, like other such inquirers, was regarded as a wizard. 
In Italy natural science continued, even in some abundance of 
life; but in Paris on the Isis, as in Paris on the Seine, its 
rudiments were soon buried under the Aristotelian and Galenical 
cenotaph by that busy gravedigger, Duns the Northumbrian, 
and were not dug up again until the day of Abbot Maurolycus 
and Vesalius nearly three centuries later. Thus one of the 
most piercing intellects and one of the most progressive societies — 
our land has produced founded no school. 
The great experimenters of the thirteenth as well as of the 
sixteenth and seventeenth centuries could hardly obtain skilled 
craftsmen for the construction of apparatus. Many observers, 
however, were themselves ingenious constructors—such as 
Archimedes, Hero, Leonardo, Brahé, Gilbert, Galileo, 
Huyghens, Hooke, Papin and, in our own time, Faraday and 
Ludwig. Roger Bacon, in his expenditure of money and 
labour upon machines, preceded Boyle and Hooke. We are 
not to suppose that Roger’s machines were clumsy and rudi- 
mentary. The Alexandrian and Byzantine Greeks, and after 
them the Arabs, had constructed apparatus of surprising elabora- 
tion and ingenuity, and Bacon’s machines would be well abreast 
of their time. In the sixteenth century, again, the reappear- 
ance of Greek preceded a new birth of natural science ; although, 
unless at Wittemberg or Basel, freedom of speech was more 
closely stifled in Europe than in the time of Abélard, for Calvin 
himself bowed before Aristotle. William Solling, Linacre, 
Grocyn and Colet were therefore forerunners of the brilliant scien- 
tific revival of which, in the seventeenth century, the establishment 
a 
4 
