PRUSSIAN BLUE PRUSSIC ACID. 



735 



was added according to the prevailing law. This 

 code was published from 1784 to 1788, in six parts. 

 The opinions of those who understood the subject 

 were requested, and prizes offered for the best com- 

 mentaries on it; and the whole was completed in 

 June, 1791, under the title "General Prussian 

 Code." Some slight faults which were pointed out 

 having been corrected, it was promulgated June 1, 

 1794, under the title Allgemeines Landrecht. The 

 work has, from the first, held a high rank, and only 

 one distinguished voice has been raised against it, 

 that of John George Schlosser, in his Five Letters 

 on Legislation, and particularly on the Plan of the 

 Prussian Code (Frankfort, 178990, 2 parts), 

 which, on the whole, take the same ground as Von 

 Savigny lias lately done (Ueber den Beruf unserer 

 Zeit zur Gesetzgebung, Berlin, 1815),* opposing all 

 modern codes. The reforms which have been ef- 

 fected since 1808 have greatly added to its value, 

 and the efforts for its improvement are still continu- 

 ed. Among the commentaries should be distin- 

 guished F. H. von Strombeck's Supplement to the 

 General Code for the Prussian States (Leipsic, 1824, 

 2 vols.). 



Prussia Proper includes the two provinces of 

 East and West Prussia. East Prussia is mainly 

 made up of the former duchy of Prussia, and West 

 Prussia is a part of Poland, which was taken in the 

 partitions. Konigsberg is the capital of East Prus- 

 sia. Dantzic and Marienwerder are the most im- 

 portant places of West Prussia. 



PRUSSIAN BLUE. See Blue, Prussian, and 

 Prussia Acid. 



PRUSSIC ACID, or HYDROCYANIC ACID, 

 is procured by the following process : To a quan- 

 tity of powdered prussian blue, diffused in boiling 

 water, let red oxide of mercury be added in succes- 

 sive portions, till the blue colour is destroyed. Fil- 

 ter the liquid, and concentrate till a pellicle appears 

 upon its surface. On cooling, crystals of prussiate 

 (or cyanide) of mercury will make their appear- 

 ance. These, after drying, are put into a tubulated 

 glass retort, to the beak of which is adapted a hori- 

 zontal tube, about two feet long, and fully half an 

 inch wide at its middle part. The first third part 

 next the retort is filled with small pieces of white 

 marble, the rest with fused muriate of lime. To 

 the end of this tube is adapted a small receiver, 

 which is immersed in a freezing mixture. Pour on 

 the crystals in the retort, muriatic acid in rather 

 less quantity than is sufficient to saturate the oxide 

 of mercury which formed them. Apply a very 

 gentle heat to the retort. Prussic acid will be 

 evolved in vapour, and will condense in the tube. 

 Whatever muriatic acid may pass over with it will 

 be detained by the marble, while the water will be 

 absorbed by the muriate of lime. By means of a 

 moderate heat applied to the tube, the prussic acid 

 may be made to pass successively along; and, after 

 having been left some time in contact with the muri- 

 ate of lime, may be driven over into the receiver. 

 As the carbonic acid, evolved from marble by the 

 muriatic, is apt to carry off some of the prussic acid, 

 care should be taken so as to prevent the distilla- 

 tion of this mineral acid. Prussic acid, thus obtain- 



*This work of Mr. von Savigny, \vhnsp objections against 

 the aptitude of our time, not to make, but to compile codes, 

 we by no means share, nor even consider very profound, is, 

 nevertheless, highly interesting, as might have been expected 

 from the reputation of the author. We recommend its peru- 

 sal with reference to the history of the code here in question. 

 It sets in a striking light the extreme care with which the 

 Prussian code \v:is dra>vn up, in which respect it is much dis- 

 tinguished from the French mid Austrian codes. Savigny's 

 work has boon translated under the title On the Aptitude ol 

 the present Age for Legislation and Jurisprudence, by a Bar- 

 rNter of Lincoln's Inn 'London). 



ed, has the following properties: it is a colourless 

 liquid, possessing a strong odour, somewhat resem- 

 bling that of peach blossoms ; and the exhalation, 

 if incautiously inhaled, may produce sickness or 

 fainting. Its taste is cooling at first, then hot, as- 

 thenic in a high degree, and a true poison. Its 

 specific gravity, at 44, is 0.7058 ; at 64, 0.6969 

 It boils at Slj , and congeals at about 3, becom- 

 ing crystallized with the fibrous form of nitrate of 

 ammonia. The cold which it produces, when re- 

 duced into vapor, even at the temperature of 68, 

 is sufficient to congeal it. This phenomenon is 

 easily produced by putting a small drop at the end 

 of a slip of paper, or a glass tube. Though repeat- 

 edly rectified on pounded marble, it retains the pro- 

 perty of feebly reddening paper tinged blue with 

 litmus. The red colour disappears as the acid eva- 

 porates. The vapor of prussic acid is 0.9476. It 

 was analyzed by Gay-Lussac by passing it through 

 an ignited procelain tube, containing coils of fine 

 iron wire. No trace of oxygen could be found in 

 it. The result was as follows : 



Carbon, 



Nitrogen, 



Hydrogen, 



44.S9 

 51.71 

 390 

 100. 



This acid, when compared with other animal pro- 

 ducts, is distinguished by the great quantity of nitro- 

 gen it contains, by its small quantity of hydrogen, 

 and the total absence of oxygen. When this strong 

 acid is kept in well-closed vessels, even though all 

 access of the air is prevented, it sometimes under- 

 goes decomposition in less than one hour. It be- 

 gins by assuming a reddish-brown colour, which 

 becomes deeper and deeper, until at length it de- 

 posits a carbonaceous matter, which gives a deep 

 colour to both acid and water, and emits an odour 

 like that of ammonia. When potassium is heated 

 in prussic acid vapour, mixed with hydrogen or ni- 

 trogen, there is absorption without inflammation, 

 and the metal is converted into a gray, spongy sub- 

 stance, which melts, and assumes a yellow colour. 

 Supposing the quantity of potassium employed 

 capable of disengaging from water a volume of 

 hydrogen equal to fifty parts, we find, after the ac- 

 tion of the potassium, that the gaseous mixture has 

 experienced a diminution of volume amounting to 

 fifty parts. On treating this mixture with potash, 

 and analyzing the residue by oxygen, we find that 

 fifty parts of hydrogen have been produced, and, 

 consequently, that the potassium has absorbed 100 

 parts of prussic acid vapour; for there is a diminu- 

 tion of fifty parts, which would obviously have been 

 twice as great, had not fifty parts of hydrogen been 

 disengaged. The yellow matter is prussiate of pot- 

 ash, properly a cyanide of potassium, in analogy 

 with the chloride and iodide of potassium, formed 

 when the vapour of muriatic and hydriodic acid is 

 made to act upon potassium. The base of prussic 

 acid thus divested of its hydrogen, to which it owed 

 its acidifying quality, is called cyanogen by Gay- 

 Lussac, in allusion to its being the basis of the blue 

 colour of prussian blue. It is obtained by heating 

 the cyanide of mercury in a small glass retort. It 

 soon blackens, and melts like animal matter, at the 

 same time disengaging the cyanogen in abundance. 

 This substance, which is the true radical of the acid 

 under consideration, is possessed of the following 

 properties: It is a permanently elastic fluid, of a 

 strong and penetrating odour, and a density, when 

 compared with air, of 1.8. It is inflammable, and 

 burns with an intensely beautiful bluish flame, bor- 

 dering on purple. It consists of nitrogen 20.654, 

 and carbon 25.418, and is, therefore, a bicarlmiet 



