Vol. XI. No. 270. 



THE AGRIt'CLTURAL NEWS. 



279 



The heating to which the keriieLs are subjected in the oil 

 mill is probably sufticient in most Ciises to reduce the to.xicity 

 to some extent, though this reduction is usually not enough 

 to remove all danger from feeding susceptible animals. 



The careful fermentation of the kernels or meal seems to 

 reduce the toxicity to a considerable extent. 



All the cotton varieties that were tested, that were grown 

 on the same jilot of ground during the same season, showed 

 no difference in the toxicity 



Sea Island seed obtained from Porto Rico was extremely 

 toxic. 



We have no evidence whatever to show that pyrophos- 

 phoric acid has anything to do with cotton seed meal 

 poisoning. 



MANORIAL NITROGEN FROM THE 



ATMOSPHERE. 



A i)aper on the manufacture of nitrates from the atmo- 

 sphere was read by Mr. E K. Scott before the lloyal .Society 

 of Alts on May 1.5, 1912, Sir William H unsay, K.C'.B , I'M! S , 

 being in tlie chair, and the following Jeta'ls are taken liom 

 the account presented in the .Journal of that Society for May 

 17. The information that is of most interest in this place is 

 that connected with the manufacture of c.ilciuui nitrate and 

 calcium cyanan;ide, and it is to this that special attention 

 will be given. 



t'ALOlt'M NiTRATj;. Before dealing with this, the paper 

 presents a table showing that the production of sulphate of 

 ammonia in England from the chief sources was, in 1906, 

 1909 and UUO, •289,:i91 tons, .349,143 and 367,.'3t!7 tons. 

 Another table shows that the exports (if sodium nitrate from 

 Chile increased from 935 tons in 1830 to 1,050,000 tons in 

 1890, with further progression from 1,970,000 tons in 1908 

 t'' 2,4'2O,40O tons in 1911. A third table is reproduced 

 below, which gives the present and future installations of the 

 Norwegian Hjdro-electric Nitrogen Cn.:^ 



Vear. Horse power. Name of Installation. 



1903 25 Experimental plant at Frogoerkilen 



1903 160 Experimental plant at Aidcerlnkken 



1904 660 Arendal 



1905 45,000 First Notodden (Svaelgfos) 

 1910 15,000 Second Xotodden (Lienfos) 



1912 140,000 First IJjukan Installation 



1913 120,000 Second Kjukan Installation 



1914 70,000 Vamma 



1915 80,000 Matre 



1916 70,000 Tyin 



These are u.sed for making calcium nitrate, or lime nitro 

 gen; a further table gives a list of the plants for the mauu- 

 tacture of calcium cyanamide (in Europe, .Japan :ind America). 



A description follows of the Birkeland-Eyde furnace and 

 its use in making calcium nitrate. As this was described at 

 length in the Agricultural News, Vol. VIII, p. 325, it does 

 •require further consideration here An account is given of 

 the Schonherr furnace, also for making calcium nitrate. In 

 this, as it h installed at Christiansand, an electric arc 16 

 feet long is maintained in a long vertical iron tube, each 

 furnace taking 600 horse-power; the arc is kept in the centre 

 of the tube by blowing the air through with a whirling 

 motion. The air receives a preliminary heating by the 

 employment of the hot gases from the furnace; it is then 

 rapidly cooled after becoming niixe<l with the highly 

 heated nitric oxide formed, and the mixture leaves the 

 top of the cooler with a temperature of about 1,200''C'. 



At Christianaand, the plant is not actually being used for 

 making calcium nitrate, but for obtaining solium nitrite for 

 employment in producing aniline dyes and similar substances. 



After a statement of the theory of the fixation of 

 nitrogen has been given, a detailed account is presented of 

 the installation at Iljukanfos; it seems that the Birkeland- 

 Eyde furnace is preferred to the Schonherr furnace as it is 

 more compact and cheaper to build, the latter requiring to be 

 built very high if is desired to increase its output. 



The principle of the Pauling furnace depends upon the 

 action of the horn break lightning arrester. In some installa- 

 tions it consists of two hollow iron electrodes arranged to 

 form an open \, at the lowest point of which are two adjust- 

 able lighting knives. The etiect of the heated air, of the 

 presence of the magnetic field, and particularly of a blast of 

 lieated air that i^< provided, is that the arc runs t.i the upper 

 part of the \', forming a triangular sheet of Hame about 

 a yard wide at the upper part of the V. In this apparatus, 

 the cooling is etlected by the action of cooled gas and air 

 winch is arranged to strike into the top of the arc tlame. 

 The article gives several exanrples of installations employing 

 this ty[ie of furnace. The acid solution obtained by the 

 proce.ss contains 50 per cent, of nitric acid. 



cvLcii'M cv,\N AMIDE. After referring to the manner 

 of discovery of calcium cyanamide, or nitrolim, the article 

 describes its manufacture at the Odda works. Here, the 

 calcium carbide employed is crushed and ground to powder 

 which is filled into electric furnaces in which the temperature 

 is raised to 800 to 1,000°L'. The electric current is allowed 

 to piss for twenty- five hours, while nitrogen is passed 

 through the mass; at the end of thirty-five hours all the gas 

 is absorbed. At Odda, 196 furnaces make about 30 tons of 

 calcium cyanamide, containing 18 per cent, of nitrogen, in 

 twent3--four hours. The product is crushed and ground fine, 

 and packed in a paper-lined bag which is put into one or 

 two jute bags, the latter being the case for export to tropical 

 countries. Recent improvements at the OJda works have 

 increased the output from 12,000 to 15,000 tons per annum. 

 It should be noted that calcium C3'anaaiide is not only used 

 as a manure: very pure ammonium sulphate is obtained from 

 it by treating it with superheated steam, and ammonium 

 nitrate and dicyandiamide are made from it. 



The chief interest of the electrical fi.xation of nitrogen 

 is its enndoyment for making artificial manures, as has been 

 described. It also has other uses, chiefly in the direction 

 of the manufacture of ammonium nitrate, dicyandiamide and 

 nitric acid for use in connexion with explosives. The manu- 

 facture of the last product is likely to be of the greatest 

 importance in view of its employment in making guncotton, 

 dynamite and smokeless powders, and this matter is of 

 s()ecial weight when it is considered that: 'A few rounds 

 from a broadside of modern guns blows away into the air 

 as much nitrogen as was used during the whole course of 

 a war of the last century. 



After making reference to other matters of interest ia 

 connexion with the subject under discussion, the article before 

 presenting its general conclusion gives attention to a proposal 

 that is being made to utilize the water from irrigation dams, 

 in India, for manufacturing manures; in this case, the manu- 

 facture could only continue for nine months in the year, 

 as in the other three the water would be requred for irriga- 

 tion, but this does not militate against the scheme, as the 

 furnacis for the processes can be easily shut down and 

 started at any time. In the scheme, it is proposed to use 

 30,000 h [P., which is expected to give 37,000 tons of calcium 

 cyanamide, containing 18 to 20 per cent, of nitroge-i, in the 

 nine months. 



