HAIIDWICKE'S SCIENCE. GOSSIP. 



131 



some hay to keep them clean and warm. Eeed them 

 upon scalded bread and rape-seed, mixed with the 

 yolk of hard-boiled egg;. The rape-seed should be 

 soaked for twelve hours, then simmered for a few 

 minutes, then strained and rolled with rolling-pin, 

 taking care to get as many of the husks away as 

 possible : it will then be ready for mixing. This pre- 

 paration will do for almost any kind of young birds : 

 they should be fed every two hours, from early mom 

 until sunset. 



The Hawhuch so brought up will answer to a 

 name if frequently mentioned at feeding-time. I 

 have heard of them imitating a few words ; and 

 indeed the formation of the bill seems to favour 

 such a remark. Those I brought up from the [nest 

 made an attempl, but I am sorry to say I cannot 

 give any account of their ability, as they died in 

 moulting. My impression is that they could talk. 



C. J. W. RUDD. 



THE PRODUCTS OF WASTE. 



rrMLE number of important commercial products 

 -*- now manufactured from m.aterials which were 

 formerly thrown away, being at first sight valueless 

 and repulsive, has within the last ten years been 

 marvellously increased. 



Those gorgeous colours the aniline dyes, exhibit- 

 ing almost every shade of the solar spectrum ; 

 stupendous blocks of alum ; beautiful yellow and 

 red crystalline masses of ferro- and ferri-cyanide of 

 potassium ; enormous cakes of paraffin, a chemical 

 curiosity a few years ago, but now one of the 

 largest of our manufactures ; the variety of lucifer- 

 matches in connection with the development and 

 production of phosphorus ; the almost endless com- 

 binations for artificial manures ; the still greater 

 assortment of paper in its useful applications ; — 

 all these might have been seen together in the last 

 exhibition, though but few perhaps of the many 

 thousands who gazed with pleasure at that interest- 

 ing collection were aware that they were mere 

 chemical products of the dust-heap and sewer. Dirt 

 has been aptly defined as valuable matter in the 

 wrong place ; and that such is the truth is evident 

 from the fact that all the manufactures first al- 

 luded to, as well as those of Prussian blue, disin- 

 fectants, glue, &c., have sprung into existence by 

 the application of chemical principles to such waste 

 products as coal-tar, gas-vrater, rags, and bones. In 

 the destructive distillation of coal for the production 

 of ordinary gas, a quantity of offensively-smelling 

 water and a considerable bulk of tarry matter are 

 also produced. These were formerly thrown away 

 as useless and deleteriou?, but now they are utilized. 



The noxious odour of the gas-water is due to 

 the presence of sulphur and ammonium compounds, 

 and by simply adding sufficient quicklime the alka- 



line compounds are decomposed and ammonia gas 

 is liberated. This is conducted into chambers filled 

 with carbonic acid gas, and thus the common salt, 

 known as carbonate of ammonium, is produced. More 

 than 2,000 tons of this useful chemical arc annually 

 made from refuse gas-water. If instead of quick- 

 lime, hydrochloric acid be added, sal-ammoniac is 

 obtained, from which nearly all the medicinal pre- 

 parations of ammonia are produced. The quantity 

 of sal-ammoniac thus manufactured from year to 

 year exceeds 4,000 tons. If again sulphuric acid be 

 employed in the place of hydrochloric acid, sul- 

 phate of ammonium is the result, about 5,000 tons 

 of which are annually used for manures. When to 

 a solution of sulphate of ammonium, one of sulphate 

 of aluminium is added, the crystalline substance 

 called alum is obtained, so generally useful in the 

 arts. The sulphuric acid used in preparing alum 

 may also be eliminated from gas-water. The sul- 

 phur impurities referred to before are removed by 

 means of a mixture of sav/dust and iron, sulphide 

 of iron and water being produced ; air is then 

 passed through the mixture, the effect of which is 

 to convert the sulphide of iron back again into oxide, 

 the sulphur at the same time separating in the form 

 of powder. The sulphur is then burned in a pro- 

 perly constructed furnace, and by causing the fumes 

 to combine with nitrous and aqueous vapours in 

 leaden chambers, sulphuric acid is obtained. 



Let us pass now to the tarry matter, the other 

 waste product of the distillation of coal. This is 

 a very complex body, containing a large number of 

 substances, most of which are volatile, some acid, 

 some alkaline, and some neutral. By appropriate 

 chemical means these components of crude coal-tar 

 are obtained in a state of purity. The lighter por- 

 tions, known as coal-naphtha, consist principally of 

 benzol, a liquid of great utility in the arts. By 

 treating benzol with nitric acid, nitro-benzol is pro- 

 duced, which is used, on account of its sweet taste 

 and almond-like odour, to perfume soaps and flavour 

 confectionery. Aniline, the base of all the dyes 

 bearing that name, is obtained from the action of 

 nascent hydrogen or nitro-benzol. Carbolic acid is 

 another product of the fractional distillation of coal- 

 tar. By the action of nitric acid, carbolic acid is 

 converted into carbazotic acid, which is now used as 

 a yellow dye. Perhaps the most interesting of all 

 the products of coal-tar is solid paiaffin, a colour- 

 less crystalline fatty substance, which may truly 

 be termed "condensed coal-gas." It is found na- 

 turally in the coal-measures and other bituminous 

 strata, constituting the minerals known as fossil 

 wax, ozokerit, &c. It exists also in solution in 

 many kinds of petroleum, and may be obtained by 

 distilling off the more volatile portions and expos- 

 ing the remainder to a low temperature. The greater 

 bulk of paraffin is, however, obtained from coal-tar. 

 The oil produced from paraffin will only burn in the 



