108 REPORT— 1861. 



Before concluding this Report, tliere is one fiict which I think internal 

 radiation may serve to explain in some such way as the following. Suppose 

 we have two substances opposite one another, one having the temperature 

 of 0", and the other of 100°, the latter will of course lose heat to the former ; 

 let us call its velocity of cooling 100. Suppose now that, while the first 

 surface still retains the temperature 0°, the second has acquired that of 400° ; 

 then we might naturally expect the velocity of cooling to be denoted by 400 ; 

 but by Dulong and Petit's law it is much greater. The reason of the increase 

 may perhaps be thus accounted for : — At the temperature of 100° we may 

 suppose that only the exterior row of particles of the body supplies the radia- 

 tion, the heat from the interior particles being all stopped by the exterior ones, 

 as the substance is very opake for heat of 100°; while at 400°, for the heat 

 of which the particles are less opake, we may imagine that part of the 

 radiation from the interior particles is allowed to pass, thereby sM'elling up 

 the total radiation to that which it is by Dulong and Petit's law. 



On the Recent Progress and Present Condition of Manvfaduring 

 Chemistry in the South Lancashire District. By Drs. E. Schunck, 

 R. Angus Smith, und H. E. Roscoe. 



It has been frequently suggested by persons engaged in manufacturing che- 

 mistry in this neighbourhood, that, as Manchester is the centre of a large 

 district in which the growth of those branches of industry immediatdy de- 

 pendent upon chemical science has been so extraordinarily rapid, and in 

 which their extent is now so vast, it would be fitting and desirable to pre- 

 sent to the Chemical Section of the British Association, at its Meeting in 

 Manchester, a short report on the recent progress and present condition of 

 the chemical manufactures of the South Lancashire district. 



In drawing up such u Report, those to whom the task of collecting and 

 editing the matter was entrusted have endeavoured, in the first place, to give 

 some idea of the progress which has been made in the trade, by describing 

 as concisely as possible those new processes, or those improvements on old 

 ones, in which any point of sufficient scientific interest presented itself; and 

 in the second place, to give a statistical account, as accurate as possible, of the 

 present yield of the very large number of chemical works in the South Lan- 

 cashire district. As a description of the rise of the Lancashire chemical 

 trade from its commencement would have much exceeded the limits of such a 

 Report, the authors decided upon confining themselves, as a rule, to the collec- 

 tion of facts regarding the improvements and new processes introduced du- 

 ring the last ten years. Notwithstanding this limitation it has, however, been 

 found that the labour of arranging the matter was much more considerable 

 than was at first supposed ; and the authors feel that, in spite of the great 

 amount of time and trouble they have expended upon it, the Report is still 

 far from complete, and they fear that in one or two minor points inaccuracies 

 may have crept in : they believe, however, that several points of great scien- 

 tific interest will be presented to the notice of the Section — points which 

 hitherto have only been known to the practical manufacturer; and they feel 

 sure that the statistics they have been able to collect will give to the scientific 

 world a notion of the importance, in a national point of view, of the chemical 

 trade of South Lancashire. 



The authors wish especially to remark that by far the largest portion of 

 the facts and statements which they are about to lay before the Section have 



