TRANSACTIONS OF THE SECTIONS. 37 



racter, according' to tlie tind of coal it is obtained from, and that this difference is 

 mainly due to the relative proportions of oil lighter than water and of oil heavier 

 than water. In the case of the oil obtained from the kind of coal commonly used 

 as fuel, the proportion of heavy oil is so large that the product closely resembles 

 the coal-tar of gas-works in all its outward characters, although the oUs lighter 

 than water which it contains are identical with those contained in crude paraffin 

 oil, as it is usually manufactm-ed from particular kinds of coal and other bituminous 

 minerals, which are exceptional in so far as they yield by distillation a product 

 containing the light oils in much larger proportions than the heavy oils. 



On Useful Applicatioiis of Slag from Iron Smelting. By Dr. B. H. Paul. 



He said slag was of a nature between porcelain and glass. Attempts had been 

 made to cast the slag into blocks as it issued from the furnace, to be afterwards 

 used as artificial stone, but all attempts of this kind had failed. The application 

 proposed with slag at the present tmie was to convert it into bricks for building. 

 This was done by a simple and ingenious contrivance. A gentleman had suc- 

 ceeded in blowing the slag into a state of very fine division, by sending steam or 

 air into it, just as it flowed from the blast furnace in the liquid state. It was thus 

 blown into a substance resembling wool in appearance. This substance was taken 

 and ground into dust, mixed with lime, subjected to powerful pressiu'e, and made 

 into bricks, of which he exhibited some examples. These bricks required no fire. 

 After being pressed, they were allowed to dry, and could be used at once, the 

 influence of the atmosphere producing a slow kind of hardening. It was also 

 intended to use the powder as a manure. 



On the Black Stones which fell from tJie Atmosphere at Birmingham in 1858. 

 By Dr. T. L. Phipson, F.C.S. Lond. 

 These stones, which have hitherto been regarded as aerolites, fell at Birming- 

 ham in gi-eat numbers during a violent storm which broke over that town in the 

 month of August 1858. Several of these stones have recently been forwarded to 

 me by Mr. W. B. Beale, in order that I might submit them to analysis. They 

 are small, angular, and black, presenting here and there a few indications of 

 crystallization. They act very slightly on a magnetic needle, but the action is 

 sensible. They give a lightish-coloured streak, and when finely pulverized are 

 partially soluble in hydrochloric acid. The analysis which I have made of them 

 has proved to me that these stones are not aerolites, but small fragments of basalt 

 rock, similar to that which exists at a few leagues from Birmingham, near the 

 parish of Rowley. They have given me — 



Silica 4613 



Alumina 1625 



Protoxide of iron 8'86 



Peroxide of iron 3'71 



Lime 1125 



Magnesia 674 



Alkalies (by difference) 3-76 



Water 330 



10000 

 The specific gravity of these stones is about 2-7 ; they fuse with some difficulty 

 on the edges before the blowpipe ; tvhen heated quietly in a platinum crucible, they 

 emit a marked odour of ozone. It is evident to me that these stones, which fell 

 in great numbers in Ann-street and other adjacent streets of the town of Bir- 

 mingham, were can-ied there by a waterspout ; as was also the case, doubtless, with 

 the curious faU of hay which I observed in London in June 1861, and described 

 in the Coniptes JRendus of the Paris Academy of Sciences, and the remarkable fall 

 of ironstone which occurred in August 1841 at Iwan in Hungary. The sizes of 

 the pieces of this ironstone which fell varied from that of a grain of hemp-seed 

 to that of a nut. The black stones which fell in Birmingham are about the size 

 of nuts, to judge from the specimens I have examined. 



