April 28, 1910J 



NATURE 



26q 



]?poch-making experiments, and (in 1752) proposed to pro- 

 tect buildings b^' the lightning-rod. Black, the friend of 

 Watt, and the enunciator of the principle of " latent heat," 

 produced his first important work as a thesis for his M.D. 

 degree in 1754. 



In the earlier part of the century the power of mathe- 

 matics in enabling us to grapple with the most abstruse 

 problems of nature was first clearly demonstrated. In the 

 latter part the foundations were laid on which the modern 

 science of chemistry was built. The intervening years were 

 not characterised by any marked progress in abstract 

 science. 



The Royal Society (to which a charter had been granted 

 in 1662) was now firmly established at the head of British 

 Science. Though it was still deemed a suitable object for 

 the occasional shafts of humorists, and though it was 

 sometimes attacked by quacks whose pretensions it declined 

 to countenance, it \vas recognised and respected by all 

 serious students of science at home and abroad. It had 

 gathered to itself the best thought of the country, and was 

 affording to what would otherwise have been the isolated 

 efforts of scientific pioneers the advantage of coordination 

 and cooperation. 



Scientific attention was then principally, though by no 

 means exclusively, directed to astronomy and to explora- 

 tion. The transits of Venus of 1761 and 1769 had been 

 predicted by Halley, and great importance was attached 

 to their proper observation. An Act of 1743 offered a 

 reward of 20,000/. for the discovery of a north-west 

 passage, and later the discoveries of Captain Cook re- 

 ceived full scientific recognition by the award of the Copley 

 medal. 



Perhaps no better indication of the state of scientific 

 progress at any time in England could be found than is 

 provided by the list of the Royal Society's Copley medal- 

 lists. In 1 73 1 and 1732 the medal was awarded to Stephen 

 Gray,' the ingenious electrician who contrived a method 

 of sending signals by means of frictional electricity, and 

 who made, therefore, the first electric telegraph. It must, 

 however, be added that the award seems to have been 

 rather in the nature of acknowledgment of a skilful experi- 

 ment than of appreciation of an important discovery. 

 Bradley received the medal in 1748 for his discovery of 

 the aberration of light, and Harrison in 1749 for his 

 chronometer. In 1753 it was given to Franklin for the 

 lightning-rod, and in 1758 to Dollond for his achromatic 

 telescope. 



The nature of these last three awards shows the tendency 

 of the time towards practical rather than towards abstract 

 science, and justifies the conclusion that the leaders of 

 scientific thought of those days were working rather for 

 practical results than for the advance of theoretical know- 

 ledge. 



Iron. 



The history of the origin and growth of the iron manu- 

 facture in England has been often told. The first step in 

 its progress was the substitution of coal for wood charcoal 

 in the process of reducing the metal from its ores. In 

 the ironworks of Sussex and elsewhere the iron was made 

 on open hearths, or small furnaces, by the help of bellows 

 worked by hand or water. In early times the natural force 

 of the wind was utilised, which, as an early WTiter says, 

 " Savpth the charge of the bellowes and of a milne to 

 make them blow." 



In such furnaces, with their moderate temperatures, 

 uncoked coal could not be used, and the sulphur and other 

 components of the coal affected the product injuriously. 

 Nevertheless, numerous efforts were made — more or less 

 successfully — to use the cheaper and more abundant fuel, 

 and but a very few years before the special date with 

 which we are concerned, the new method may be said to 

 have been placed on a commercial footing. 



It was at Coalbrookdale,* in Shropshire, that .Abraham 

 Darby established the manufacture of iron by coal about 

 1730 or 1735. He treated the coal as the charcoal-burners 

 treated wood, and found that in the resulting coke he had 

 the fuel he required. In 1754 he had some seven furnaces 



Gray it was who first proposed the theory of positive and negatire 

 electricity. 



" Til's is the usual spelling. Percy has Colebrook, and gives Coldbrook 

 as the original name. 



NO. 2 113, VOL. 83] 



(presumably small blast furnaces or reverberatory furnaces), 

 and for blowing these he had five *' fire engines " (steam 

 or atmospheric engines), which pumped water to drive 

 water-wheels which worked the bellows, the " rotative " 

 engine not having then been invented. Such was the 

 point that the manufacture of iron had reached at the 

 time about which we are concerned. A few years later, 

 in, or shortly after, 1760, Dr. Roebuck used blowing 

 engines at the Carron Iron Works in Stirlingshire. These 

 had four single-acting cylinders of cast-iron 4 feet 6 inches 

 in diameter, and the pistons, of which the stroke w^s 

 4 feet 6 inches, were worked in alternation, so that a 

 continuous and tolerably equal blast was maintained.' 

 They were constructed by Smeaton. 



It was the father of this Abraham Darby, Abraham the 

 elder, who introduced into England about 1706 the art of 

 casting iron vessels. The story, old and well known as it 

 is, will bear re-telling. Early in the century John Darby 

 brought over some Dutch brass-founders, and set up a 

 foundry in Bristol. Here he tried to make iron pots 

 instead of brass, but failed, until his Welsh apprentice. 

 John Thomas, " thought he saw how they had missed it," 

 tried the experiment, and, working secretly with .Abraham 

 Darby (the son of John), cast the same night an iron pot. 

 '■ For more than 100 years after the night in which 

 Thomas and his master made their successful experiment 

 of producing an iron casting in a mould of fine sand, with 

 its two wooden frames and its air-holes, the same process 

 was practised and kept secret at Colebrook Dale, with 

 plugged key-holes and barred doors." 



It is about this date (1740, or a little later) that Hunts- 

 man perfected the process of making cast steel, which is 

 still employed. Before this, " Steel was never melted and 

 cast after its production." " By whatever method pre- 

 pared, whether by the addition of carbon to malleable iron, 

 or by the partial decarbonisation of pig iron . . . steel in 

 mass was never obtained homogeneous." There is no 

 need to describe the process, with its purely technical 

 details. It may be sufficient to record the fact that the 

 problem of producing ingots of steel of uniform composi- 

 tion w^as solved by Benjamin Huntsman, and that, as his 

 secret method of working w-as stolen by a workman, it 

 soon came to be generally employed in the Sheffield steel 

 trade. 



These early founders of the great British iron trade were 

 soon followed by many others, chief of whom was Henr>' 

 Cort with his invention of puddling (1783), and the manu- 

 facture, stimulated, in the later days of the centur\', to 

 meet the rapidly growing demand for iron caused by the 

 development of machinery and the steam engine, soon 

 reached a most important place among the industries of 

 the country. 



Copper and Brass. 



Without considerable research it might be difficult to 

 give anything like a trustworthy account of the condition 

 of metalliferous mining and metallurgy- in the middle of 

 the eighteenth century, and even if the labour were under- 

 taken it would be difficult to ensure accuracy of result. 

 Copper, tin, and lead have been mined and smelted in 

 Great Britain from ver>- early dates. Zinc, in the metallic 

 state, was imported from China (or, at all events, from 

 the East) in the early part of the seventeenth century,' 

 but it does not seem to have been made in England until 

 a century later. 



Percy, while he professes himself unable to give a com- 

 plete history of copjier-smelting in England, tells us of 

 earlv copper-mines in Cumberland and Northumberland, 

 and thinks that the ores were smelted on the spot ; but 

 copper was imported from Hungary and Sweden, while 

 calamine (zinc carbonate) was allowed to be exported as 

 ballast. About the end of the seventeenth and the 

 beginning of the eighteenth century copper-smelting was 

 being carried on in Yorkshire and Lancashire, also a little 

 later in Cornwall, in Gloucestershire, and at Bristol. The 

 date of the establishment of copper works at Swansea 

 (now the centre of the trade) is given as 1720, though 

 Percy states that smelting was carried on in the Princi- 

 palitv" before that date. Brass (an alloy of copper and 

 zinc), as distinct from bronze (copper and tin), was known 



1 Percv. " Iron and S'e«!."p. 8?<). 



^ Percy's " Metallurgy " (iS5i), p. 519, 



