VINEGAR VINEIS. 



825 



gar is produced in the course of the summer. Vine- 

 gar obtained by the preceding method has more or 

 less of a brown colour, and a peculiar, but rather 

 grateful smell. By distillation in glass vessels, the 

 colouring matter, which resides in a mucilage, is 

 separated ; but the fragrant odour is generally re- 

 pLiced by an empyreumatic one. Its specific gra- 

 vity varies from 1-005 to 1-015. 



A crude vinegar has long been obtained from 

 wood, for the use of the calico printers. It is 

 sometimes known under the name of pyroligneous 

 acid. The following arrangement of apparatus is 

 found to answer very well in its preparation. A se- 

 ries of cast iron cylinders, about four feet diameter 

 and six feet long, are built horizontally in brickwork, 

 so that the flame of one furnace may play round 

 about two cylinders. Both ends project a little 

 from the brick work. One of them has a disc of 

 cast iron well fitted and firmly bolted to it, from 

 the centre of which disc an iron tube, about six 

 inches in diameter, proceeds and enters at a right 

 angle, the main tube of refrigeration. The diame- 

 ter of this tube may be from nine to fourteen inches, 

 according to the number of cylinders. The other 

 end of the cylinder is called the mouth of the retort. 

 This is closed by a disc of iron, smeared round its 

 edge with clay lute, and secured in its place by 

 wedges. The charge of wood for such a cylinder 

 is about 800 pounds. The hard woods, oak, ash, 

 birch, and beech are alone used. The heat is kept 

 up during the day time, and the furnace is allowed 

 to cool during the night. Next morning the door is 

 opened, the charcoal removed, and a new charge of 

 wood is introduced. The average product of crude 

 vinegar or pyroligneous acid is thirty-five gallons. 

 It is much contaminated with tar, is of a deep brown 

 colour, and has a specific gravity of 1-025. Its total 

 weight is therefore about 300 pounds. But the 

 residuary charcoal is found to weigh no more than 

 one-fifth of the wood employed. Hence, nearly one 

 half of the ponderable matter of wood is dissipated in 

 incondensable gases. The crude acid is rectified 

 by a second distillation, in a copper still, in a body of 

 which about two gallons of viscid tarry matter are 

 left from every hundred. After this treatment, it pre- 

 sents the appearance of a transparent, brown vine- 

 gar, having a considerable empyreumatic smell, and 

 a specific gravity of 1*013. Its acid powers are 

 superior to those of the best household vinegar, 

 in the proportion of three to two. By redistil- 

 lation, saturation with quick-lime, evaporation of 

 the liquid acetate to dryness, and gentle torrefac- 

 tion, the empyreumatic matter is so completely dis- 

 sipated, that, on decomposing the calcareous salt by 

 sulphuric acid, a pure, perfectly colourless, and 

 grateful vinegar arises in distillation. Its strength 

 will be proportional to the concentration of the 

 decomposing acid. 



The acetic acid of the chemist may be prepared as 

 follows : 1. Two parts of fused acetate of potash, 

 with one of the strongest oil of vitriol, yield, by 

 slow distillation from a glass retort into a refriger- 

 ated receiver, concentrated acetate acid. A small 

 portion of sulphureous acid, which contaminates it, 

 may be removed by redistillation from a little ace- 

 tate of lead. 2. Or four parts of good sugar of lead, 

 with one part of sulphuric acid, treated in the same 

 way, afford a slightly weaker acetic acid. Or, with- 

 out distillation, if one hundred parts of well dried 

 acetate of lime be cautiously added to sixty parts of 

 strong sulphuric acid, diluted with five parts of 

 water, and digested for twenty-four hours, and 



strained, a good acetic acid, sufficiently strong for 

 every ordinary purpose, will be obtained. Acetic 

 acid is composed of 



Carbon, . 46-83 



Hydrogen, 6-33 



Oxygen 46'82 



Acetic acid dissolves resins, gum-resins, camphor, 

 and essential oils. Its odour is employed in medi- 

 cine to relieve nervous headache, fainting fits, or 

 sickness occasioned by crowded rooms. In a slightly 

 dilute state, its application has been found to check 

 hemorrhage from the nostrils. Its anti-contagious 

 powers are now little trusted to. It is very largely 

 used in calico printing. Moderately rectified pyro- 

 ligneous acid is much employed for the preservation 

 of animal food. Sulphuric acid is sometimes frau- 

 dulently mixed with acetic acid and common vine- 

 gar, to increase their acidity. This adulteration 

 may be detected by the addition of a little chalk. 

 With pure vinegar, the lime forms a limpid solution, 

 but with sulphuric acid,, a white insoluble gypsum. 

 Muriate of barytes is a still nicer test. British 

 fermented vinegars are allowed by law to contain a 

 little sulphuric acid ; but the quantity is frequently 

 exceeded. Copper is discovered in vinegars by 

 supersaturating them with ammonia, when a fine 

 blue colour is produced; and lead, by sulphate of 

 soda, hydrosulphurets, and sulphureted hydrogen. 

 None of these should produce any change on 

 genuine vinegar. Salts consisting of the several 

 bases, united in definite proportions to acetic acid, 

 are called acetates. They are characterized by the 

 pungent, smell of vinegar, which they exhale on the 

 affusion of sulphuric acid, and by their yielding, on 

 distillation in a moderate red heat, a very light 

 odorous and combustible liquid, called pyro-acetic 

 spirit. They are all soluble in water ; many of 

 them so much so as to be uncrystallizable. About 

 thirty different acetates have been formed, of 

 which only a very few have been applied to the 

 uses of life. 



VINEIS, PETRUS DE, oa PIETRO DELLE 

 VIGNE, one of the most distinguished jurists and 

 politicians of the 13th century, a native of Capua, 

 the son of poor parents, studied in Bologna. Chance 

 made him known to the emperor Frederic II. who 

 soon raised him to the highest offices. He at last 

 became the emperor's chancellor, and as such de- 

 fended his master, orally and in writing, against the 

 monstrous assumptions of the popes Gregory IX. 

 and Innocent IV. The libels of the former were 

 refuted by Vineis with learning and wit ; and it- 

 was owing in no small degree to his efforts, that 

 the excommunication fulminated against the em- 

 peror remained without effect. When Innocent 

 IV. in 1245, cited the emperor before the council 

 of Lyons, Vineis defended his absent master with 

 great ability. Yet, notwithstanding all these ser- 

 vices, his enemies succeeded in making the emperor 

 suspect that Vineis had tried to poison him ; and 

 he ordered his chancellor to be blinded and thrown 

 into a prison in Pisa, where the unfortunate man 

 put an end to his life, in 1429, by dashing his head 

 against a pillar ; on account of which we find him 

 in Dante's Hell among the suicides, relating his 

 mournful story. {Canto xiii, Inferno.) This is a 

 dark spot in the history of this otherwise great em- 

 peror. The writings of Vineis, yet extant, are a 

 treatise De Potestate imperiali, and six books of 

 letters on the deeds of Frederic II. mostly in the 

 name of the emperor, and written in bad Latin, 

 which is to be attributed to the low state of learn- 



