August 19, 1909] 



NA TURE 



Cyanamide is made in France at the village of 

 -Notre Dame de Brianijon, near to JNIontiers (Savoie). 

 .Abundant water-power is available, and is, of course, 

 an essential condition for the success of the industry. 

 At the power station there are now three turbines of 

 2200 h.p., but provision is made for more when neces- 

 sary; these produce a three-phase current of 15,000 

 ■volts, which is conducted a distance of 11 km. to 

 the factory. There it is transformed ; part is used 

 for making calcium carbide, and part for making 

 cyanamide. The calcium carbide obtained has a 

 p'uritv of 8o'5 per cent., estimated with sufficient ac- 

 curacy by measuring the volume of gas evolved on 

 treatnient with water. Nitrogen is prepared by 

 Linde's method. Liquid air is fractionated, and the 

 vapours made to pass through a column, where they 

 meet with liquid air, and then, higher up, with liquid 

 nitrogen ; in these circumstances, the percentage of 

 •oxygen in the issuing vapours is reduced to 7, and then 

 finally to zero. 



The calcium carbide is broken up and placed in 

 .an electric furnace, about 300 kilos, forming the 

 ■charge. It is raised to a high temperature in presence 

 of a stream of nitrogen ; the operation may last from 

 eighteen to fifty-si.x hours. The resulting hard mass 

 is then reduced to a fine powder. The daily production 

 .is at present 10 tons, but this output could readily be 

 doubled. It is estimated that 2 tons of carbide can 

 be produced per kilowatt per year, and that 2 tons 

 of carbide combine with 500 kilos, of nitrogen. Two 

 grades of cyanamide are sold — one containing 15 per 

 •cent, of nitrogen, i.e. the quantity present in nitrate 

 of soda, the other containing 20 per cent., the quan- 

 titv present in sulphate of ammonia. The latter grade 

 also contains 20 per cent, of lime, 7 to 8 per cent, of 

 silica, oxides of iron and aluminium, and 14 per cent, 

 ■of free carbon, to which the dark colour is due. 



When added to the soil, it is rapidly decomposed 

 by bacteria to form calcium carbonate and ammonia 



CaCN, + 3H,0 = CaC03+2NH,. 



The ammonia is then nitrified and taken up by 

 plants. 



Direct field trials to ascertain its manurial value 

 were first made in igoi by Gerlach and \\'agner, and 

 Itave since been repeated in other countries. All ex- 

 periments prove its value, and show that it is com- 

 parable in its effects with sulphate of ammonia. It 

 should be applied before sowing, and may be mixed 

 with basic slag or potassic manures, but not with 

 superphosphates. The dressing recommended is 

 150 kilos, to 250 kilos, per hectare, or 2} cwts. 

 to 4^7 cwts. per acre, the smaller dressing for cereals, 

 the higher for potatoes and beets. In England it 

 would not be customary to use for these crops more 

 than half the above quantities of " artificial " nitro- 

 genous manures. 



THE "PREHISTORIC HORSE" OF BISHOP'S 

 STORTFORD. 



A COMPLETE skeleton of a horse was recently 

 found during excavations at Bishop's Stort- 

 ford. As this skeleton lay in an extended position 

 some six feet below the surface in a deposit which 

 had apparently never [:"eviously been disturbed by 

 man, it is conceivable that u '^elongs to a wild variety 

 which inhabited England in prehistoric times. The 

 Rev. Dr. Irving first thought the skeleton might 

 belong to Hipparion {Standard, May 24), but he 

 eventually came to the conclusion that it is the 

 remains of a horse of the Neolithic or Bronze age. 

 L'nfortunately, it seems to be impossible to deter- 



NO. 2077, VOL. 81] 



mine the age of the deposit in which the skeleton was 

 found.' The examination of the skull, teeth and limbs 

 indicates that the Bishop's Stortford horse differs from 

 all the known wild horses of the Pleistocene period — 

 from, c'.^"., the small, stout horse of the " elephant " 

 bed at Brighton ; the small, slender-limbed horse of 

 the Oreston Cavern, believed by Owen to be an ass 

 or a zebra; the Prejvalsky-like diluvial horse of 

 Remagen ; and the coarse-limbed horse of ^^'esteregeln. 

 On the other hand, the horse described by Dr. Irving 

 and figured in the Illustrated London Ke-ji's (June 5) 

 closely resembles a v'ariety from Walthamstow be- 

 lieved to be of Neolithic or Bronze age. This Wal- 

 thamstow horse was probably a blend of a " forest " 

 and a " steppe " variety in which the broad-browed 

 forest ancestors were dominant. The limb bones in- 

 dicate that the Bishop's Stortford horse measured 

 from 14 to i4'2 hands (56 to 58 inches) at the withers 

 — several inches more than the Walthamstow horses 

 represented in the British Museum. 



It is generally assumed that the horse did not live 

 under domestication in Britain until the end of the 

 Bronze or the beginning of the Iron age, and that 

 the native British horses up to the coming of Cajsar 

 were too small to carry men. The Bishop's Stort- 

 ford horse was, however, as large and powerful as 

 the Galloways used in border raids. Should the 

 Bishop's Stortford horse be proved to be of Neolithic 

 or Bronze ag'e, we may have to modify our views as 

 to the size "of the horses in the possession of the 

 ancient Britons. For an opportunity of examining the 

 skull and limb bones of the Bishop's Stortford horse, I 

 am indebted to the Rev. Dr. Irving. 



J. C. Ew.\RT. 



METEOROLOGICAL STUDIES AT THE 

 BLUE HILL OBSERV.iTORY.-L 



(i) T^HIS is an account of the methods employed 

 A and the results obtained at St. Louis. 

 Seventv-seven ascensions were made, and in most cases 

 good traces were obtained. The funds were supplied 

 partly bv grants from the Exposition Company and 

 from" the Hodgkins fund of the Smithsonian Institu- 

 tion, and the remainder by Prof. Rotch. 



A very large proportion of the balloons were found, a 

 proportion looked upon with envy by those engaged in 

 similar work in England, and this occurred notwith- 

 standing the fact that they were mostly sent up in 

 the evening to escape the chance of solar radiation. 



A full description oftfie method of working and of 

 calibrating the instruments is given, and every care 

 seems to "have been taken to secure accuracy in the 

 results ; but it is incorrect to say that the only method 

 of making the registration yet devised is that of 

 writing on a smoked metal surface. The plan of 

 scratching on an electro-plated but unpolished silver 

 surface has answered excellentlv in England, and Mr. 

 Field's plan of using glass silvered lightly by the 

 ordinarv solution seems to be quite satisfactory. 



The 'results from each ascent are published in 

 full, and it appears that about half the ascents afforded 

 records up to 10 kilometres in height. The general 

 conclusion is in striking agreement with thaf obtained 



1 (1) '■ Exploralion of the Air with Ballons-sindes at St. Louis and with 

 Kites at Blue Hill." By H. Helm Cliiyton and S. P. Fergmson. Pp. 92; 11 

 plates. (Cambridge, Mass. : The Observatory, 1909.) 



"Annals of the Astronomical Observatory of Harvard College." Vol. 

 Ixviii., part i., Obser\-ations and Investiciations mrde at the Blue Hill 

 Meteorological Observatory, Massachusetts, U.S.A., under the direction of 

 A. Lawrence Rotch. 



(2) " .A.nnals of the Astronomical Observatory of Harvard College." Vol. 

 Iviii., part iii., Observations and Investigations made at Blue Hill Meteoro- 

 logical Observatory, Massachusetts, U.S.A., in the year 1905, under the 

 direction of A. Lawrence Rotch. Pp. 147-228 ; 2 plates. (Cambridge, Mass. : 

 The Observatory, igoS.) 



