610 



NITROGLYCERINE 



NITROUS ETHER 



atmospheres being required to liquefy it at C. 

 Davy discovered in 1800 that it possessed anirs- 

 thetio piop.'i tie>. ami it is now used as an amrs- 

 t lu'tic in minor surgical operations. For such pur- 

 poses it is stored in the liiiuid .-tale by dentists 

 and others in wrought -iron iwttles. It is a sup- 

 |>"i I'T nf ciimhii-iiuii. and burning materials placed 

 in it continue to burn with almost as great brilliancy 

 as if placed in free oxygen. 



\itric Ofitle, NO, 18 produced by the action of 

 nitric acid on copper, silver, or mercury. It is a 

 colourless gas, which like nitrogen can only be 

 reduced to the liquid state by pressure after it has 

 been cooled to a very low temperature. Its most 

 striking character is the great readinexs with 

 which it unites with free oxygen, forming dense 

 In-own fumes, which consist mainly of peroxide of 

 nitrogen. 



\itn>nit Anfii/driiie has been described as a gas 

 easily condensable to a liquid, possessing the com- 

 position represented bv the formula N'J '.,. It 

 seems very questionable whether a single sub- 

 stance exists either in the state of gas or of liquid 

 possessing this composition. The gas which was 

 supposed to lie nitrous anhydride was certainly a 

 mixture. Although nitrons anhydride cannot be 

 obtained pure, and the corresponding acid nitrons 

 acid is an unstable substance at ordinary tempera- 

 tures, a number of nitrites, salts corresponding to 

 nitrous acid, are known. 



Peroxide of Nitrogen, NO, or N S O <( is produced 

 when oxygen and nitric oxide are mixed. It is a 

 dark-brown liquid at ordinary temperatures, which 

 boils at 22, yielding a brown vapour, and solidifies 

 at - 9, forming colourless crystals. 



Xitrir. Aii/ii/i/riite, N S O 5 , is the anhydride of nitric 

 acid, andean be obtained amongst other ways from 

 nitric acid by the action on it of phosphoric anhy- 

 dride (see NITRIC ACID). 



The following are some of the other more im- 

 portant nitrogen compounds : ammonia and the 

 ammonium stilts (see AMMONIA); the vegetable 

 alkaloids (set- ALKALOIDS) ; aniline and its deriva- 

 tives ; cyanogen and the cyanides, including hydro- 

 cyanic acid ; albnmeuoid substances ; urea and uric 

 acid ; nkro l(enzene, and other nit ro compounds ; 

 pyridine and allied substances, hydrazine com- 

 jHiumls, ptomaines, &c. See AZOTISED BODIES. 



Nitro-Klycerllie (known also as Glonoin or 

 GloHoiH-oil) can be readily prepared by dissolving 

 glycerine in equal measures of strong nitric and 

 sulphuric acids ami pouring the solution into 

 water, when the nitro-glycerine becomes precipi- 

 tated. Nitro -glycerine was discovered by Sobrero, 

 a young Italian chemist at Paris, who in 184(i 

 foiinil that by the above process he could produce 

 a highly explosive mixture. There was little idea 

 at the time of the value of the discovery, which 

 was treated solely as a chemical curiosity, until 

 alMiut fifteen years later, when Alfred Nobel, a 

 Swedish engineer and chemist, |ierceiving the value 

 of the unrecognised explosive and turning his 

 attention to its development, rapidly introduced 

 it as a blasting agent for industrial purposes. The 

 ii-w explosive was eminently satisfactory so far as 

 blasting power was concerned ; but a series of fear- 

 ful accidents, notably that to the ship European 

 at Panama in 1808 numerous expedients devised 

 to render it safe in t run-it notwithstanding - 

 called public attention to the danger inseparable 

 from ito conveyance, and in Isii'.t parliament, so 

 far as Britain was concerned, placed its veto on 

 iiitro-giycerine. 



The drawbacks which culminated in this pro- 

 hibition led to the production of the nitro-glycerine 

 ci>iii|innils, now forming a large group, notably 

 dynamite (see DYXAMITK, Vol. IV. p. 144), in 

 which ultra-glycerine, absorbed by some inert 



porous siih-tance. is thereby rendered safe from 

 the dangers incident to the employment of nitro- 

 glycerine without such treatment. N'itro glycerine, 

 as manufactured on a large scale for cimmicrcial 

 imr|M>ses, is formed by the mixture of strong nitric 

 and sulphuric acids, coolcil by water, previous to 

 )>eing introduced into a large leaden \o-el, the 

 tcni|>erature of which is kept down by water circu- 

 lating through coils inside. Glycerine is then 

 injected by compressed air as a fine spray, and 

 becomes immediately nitrated, considerable heat 

 being evolved. On the completion of the nitra- 

 tion, as indicated by the fall of temperature, the 

 mixture is run off into another leaden viel and 

 allowed to stand. In about an hour the separa- 

 tion is complete. The nitro-glycerine, after lieing 

 thoroughly washed in water and subsequently in 

 an alkaline solution to remove every trace of acid, 

 is ready for manufacture into dynamite or other 

 nitro-glycerine compounds. 



The utmost care is exercised in the above pro- 

 cesses, and any abnormal rise in temperature is 

 strictly guided against, or accidents would arise. 

 For similar reasons the materials employed in the 

 manufacture of nitro-glyeeiine are in every par- 

 ticular the best and purest attainable. Colourless 

 when pure, but having as an article of commerce 

 a pale brown colour, nitro-glycerine is a dense, oily 

 liquid, having a specific gravity of 1'6. It is 

 inodorous, but has a sweet, pungent, aromatic 

 taste ; a single drop, however, if placed on the 

 back of the tongue, will produce headache and 

 pain in the back lasting for hours, liy those 

 accustomed to handling this substance, no incon- 

 venience whatever is experienced. Nitre-glycerine 

 enters into medical prescriptions for certain diseases 

 of the heart. 



If ignited in the open air nitro-glycerine burns 

 rapidly and with a brisk (lame wit hunt any ex- 

 plosion; and if poured out in a thin sheet it ignites 

 with difficulty and burns incompletely; but it 

 explodes at once if it is exposed to a moderately 

 strong blow or concussion, to the concussion due 

 to the explosion of gun|>owder, to contact with 

 red hot iron, and especially to the action of 

 detonating mixtures and fulminates. It likewise 

 explodes on exposure to a high temperature, the 

 exploding-point for nitro-glycerine compounds being 

 ftlMiut T I''.; but 150* to 180 F. is sufficient 

 to set up decomposition in the cartridge, and this 

 will quickly raise the temperature to exploding- 

 jMiint. According to I)r Rudolf Wagner, nitro- 

 glycerine, if chemically pure, may l>c cooled down 

 to 4 without becoming solid ; that of commerce, 

 however, become* solid if exposed for a considerable 

 time to a tem]>cratnre of about 40 to 45 F., crystal- 

 lising in long needles, which are most dangerous to 

 handle, since they explode, even if gently broken, 

 with much violence. In such condition the nitro- 

 glycerine compounds should not lie used for blast- 

 ing, but can be readily thawed in a simple form of 

 {'.in heated by hot water. At 320 nit ro glycerine 

 K'gins (according to Adrian!) to decompose, giving 

 off red vapours ; and if the heat be suddenly 

 applied, or slightly raised above this point, violent 

 explosion will occur. For equal bulks nitro- 

 glycerine is calculated to be thirteen times as 

 strong as gunpowder, while for equal weights it is 

 eight times as powerful. 



Nitro-glycerine oompoondl have been employed 

 in the largest blasts that have licen made, notably 

 those at Hell Gate (see BI.ASTIM; ). The manufac- 

 ture of nitro-glycerine compound* in Great Britain 

 is strictly controlled by legislation, and carried on 

 under government supervision. See Kissel, Jliimt- 

 boot of Modern Explosives ( 1891 ). 



Nitrons Ether, or NITHITK OK KTIIVI,, 

 ,, is a very volatile ether, with an agree- 



