Nov. 21, 1884.] 



♦ KNOWLEDGE ♦ 



419 



of carbonate of soda to remove the excess of acid. It is 

 now largely used in flavouring as essence of bitter almonds. 

 Its old perfumery name was Essence of Mirbane. 



By more elaborate operations on the coal-tar product, a 

 number of other essences and bouquets of curiously imita- 

 tive character are produced ; one of the most familiar of 

 these is the essence of jargonelle pears, which flavours the 

 " pear drops " of the confectioner so cunningly ; another is 

 raspberry flavour, by the aid of which a mixture of fig- 

 seeds and apple-pulp, duly coloured, may be converted into 

 a raspberry jam that would deceive our Prime Minister. I 

 do not say tliat it now is so used, though I believe it has 

 been, for the simple reason that wholesale jam-makers now 

 grow their own fruit so cheaply that the genuine article 

 costs no more than the sham. Raspberries can be grown 

 and gathered at a cost of about twopence per 

 pound. 



AVith wine at 60s. to 100s. per dozen the case is dif- 

 ferent. This price leaves an ample margin for the con- 

 version of " Italian reds," Catalans, and other sound, 

 ordinary wines into any fancy brands that may happen to 

 be in fashion. Such being the case, the mere fact that 

 certain emperors or potentates have bought up the whole 

 produce of the chateau that is named on the labels does not 

 interfere with the market supply, which is strictly regulated 

 by the demand. 



Visiting a friend in the trade, he offered me a glass of 

 the wine that he drank himself when at home, and supplied 

 to his own family. He asked my opinion of it. I told 

 him that I thought it was genuine grape juice, resembling 

 that which I had been accustomed to drink at country iuns 

 in the Cote d'Or (Burgundy) and in Italy. He told me that 

 he imported it directly from a district near to that I first 

 named, and could supply it at 123. per dozen with a fair 

 profit. Afterwards, when calling at his place of business 

 in the West-end, he told me that one of his best customers 

 had just been tasting the various dinner wines then remain- 

 ing on the table, some of them expensive, and that he had 

 chosen the same as I had, but what was my friend to do ? 

 Had he quoted 12s. per dozen, he would have lost one of 

 his best customers, and sacrificed his reputation as a high- 

 class wine-merchant ; therefore he ijuoted 5-ts., and both 

 buyer and seller were perfectly satisfied : the wioe-mer- 

 chant made a large profit, and the customer obtained what 

 he demanded — a good wine at a " respectable price." He 

 could not insult his friends by putting cheap 12s. trash on 

 his table. 



Here arises an ethical question. Was the wine- 

 merchant justified in making this charge under the cir- 

 cumstances ; or, otherwise stated, who was to blame for the 

 crookedness of the transaction ? I say the customer ; my 

 verdict is, " Sarve him right ! " 



In reference to wines, and still more to cigars, and some 

 other useless luxuries, the typical Englishman is a victim 

 to a prevalent commercial superstition. He blindly 

 assumes that price must necessarily represent quality, and 

 therefore shuts his eyes and opens his mouth to swallow 

 anything with complete satisfaction, provided that he pays 

 a good price for it at a respectable establishment, i.e., one 

 where only high-priced articles are sold. 



If any reader thinks I speak too strongly, let him ascer- 

 tain the market price per lb. of the best Havanna tobacco- 

 leaves where they are grown, also the cost of twisting them 

 into cigar shape (a skilful workwoman can make a thousand 

 in a day), then add to the sum of these the cost of packing, 

 carriage, and duty. He will be rather astonished at the 

 result of this arithmetical problem. 



If these things were necessaries of life, or contributed in 

 any degree or manner to human welfare, I should protest 



indignantly ; but seeing what they are and what they do, 

 I rather rejoice at the limitation of consumption eifected 

 by their fancy prices. 



THE 



EXPLOSIYENESS OF COAL- 

 DUST. 



IT is the special merit of Mr. William Galloway, formerly 

 Government Inspector of Mines, now director of the 

 Dinas Colliery, near Cardiff, in South Wales, that he drew 

 the attention of mining engineers to the great danger of 

 dry coal-dust in fiery coal-mines, owing to its explosiveness, 

 in a paper, " Influence of Coal-dust in Colliery Explosions," 

 read before the Royal Society of London in 1879. 

 Although its influence was already presumed by Faraday 

 and Lyell in 1844, after an explosion in the HasweU 

 Colliery, and also proved to have existed at explosions in 

 mines near Firminy and VUlars in 1855 and 1867, by M. 

 du Souich in France, it is to ilr. Galloway the credit is due 

 of having first demonstrated its action experimentally. 

 These experiments were later on repeated by the British 

 Commission on Colliery Explosions, the results corrobo- 

 rating Mr. Galloway's \-iews. As the opinions of some 

 French mining engineers and of the French " Commission 

 sur les Explosions du Grison " did not seem to tally with 

 the English experiments, the Prussian Government Com- 

 mission on Colliery Explosions deemed it desirable to have 

 these experiments repeated on a large scale and under con- 

 ditions which would be identical with those existing in 

 fiery coal-mines. 



Thus, at the instance of one of its members, Director 

 HUt, of Aachen, the scientific technical committee of the 

 Government Commission decided upon erecting an experi- 

 mental arrangement for this purpose at the Government 

 colliery " Ka>nig " at Xeunkirchen, near Saarbriicken, 

 where natural fire-damp could be drawn in any quantity 

 from a " blower," by which the explosive gas escapes in the 

 mine from a bed of conglomerate. 



At this mine, in an old burrow of stones, an adit level 

 was constructed under the special superintendence of Mine- 

 inspector Margraf. From its mouth to the head it has a 

 length of 167 ft, and it is timbered with elliptical rings of 

 double "J" iron and lined inside with a layer of 2-in. pine 

 planks, which are tightly jointed. On one side this 

 structure is entirely buried up to the top in the old 

 bun'ow, while on the other its upper quarter is visible, and 

 is provided with thirty small windows of thick glass well 

 fixed in cast-iron frames. The head of this adit level is 

 formed by a heavy block of masonry, 12 ft. 4 in. long 

 and 9 ft. 10 in. wide, forming there a niche or recess 

 .3 ft. 10 in. deep. In this masonry seven small cast- 

 iron mortar guns, whose bores represent ordinary 

 blast - holes, are well fixed in such a manner that 

 two are close under the roof, three in the middle of the 

 head, and two somewhat above the floor. The direction of 

 their respective axes is such, that the upper guns converge 

 so as to cut the floor 10 metres from the head, while the 

 axes of the lower guns cut the roof at the same distance ; 

 the three middle guns, however, converge so that their axes 

 hit the middle of the floor at -5 metres from the head. The 

 inner end of the adit level is provided with stout wooden 

 frames, between which sailcloth can be fastened, so as to 

 form a series of chambers, of which the innermost has a 

 cubic space of about 20 cubic metres (706-3 cubic feet). 

 The firing of the guns is effected by electricity, in order to 

 produce an explosion of either firedamp or coal-dust, or of 

 both, and during the last couple of months over 200 of such 

 artificial mine explosions have taken place. 



