756 



D I S T I L L A T I ON. 



Di»tilla- 

 tion. 



Distillation 

 of wood. 



hint one precaution, to avoid an accident : When the 

 evolution of the inflammable gas becomes slow, or 

 ceases entirely, the common air comes with the flame 

 along the pipe into the close receiver, which is filled 

 with the same inflammable gas. Under these circum- 

 stances an explosion will take place, which Mill not 

 only burst the receiver, but do other injury. This evil 

 will be avoided, by placing a valve in the pipe open- 

 ing outwards, and another upon the receiver opening 

 inwards : By this means the flaming gas will be stop- 

 ped in its passage to the receiver, while the valve into 

 the receiver will open to admit the common air, to fill 

 up the vacuum. By means of the above apparatus, if it 

 be well constructed, and proper luting employed, the 

 distillation of hartshorn may be carried on almost with- 

 out smell. 



The first product consists of water, animal tar, and 

 carbonate of ammonia. A great part of the tar may be 

 separated mechanically ; the rest is subjected to a se- 

 cond distillation with a gentle heat. The liquid which 

 Comes over consists of a solution of carbonate of am- 

 monia, with a fetid animal oil, which gives it a peculiar 

 odour. This liquid has been sold in the shops under 

 the name of spirit of hartshorn. The animal matter 

 contained in this substance, was at one time thought to 

 possess certain medical virtues. This idea becoming 

 obsolete, has led to the substitution of what is termed 

 the aqua-ammonia. This is formed by distilling the mu- 

 riate or sulphate of ammonia and quicklime. The 

 lime takes the acid from the salt, setting the ammonia 

 free, which comes over in the state -of gas, and is ab- 

 sorbed by water. This liquid is called aqua-ammonia. 



In the manufacture of printed calico, a large quantity 

 of acetic acid is employed, for the preparation of certain 

 mordants. The acetic acid used for this purpose, is 

 procured from wood by distillation. 



The still is made of cast or wrought iron, and very 

 strong, so as to bear a red heat. The wood is piled up 

 in the still in the state it is Used to make charcoal. The 

 heat required is similar to that required for distilling 

 bone9. Water and vegetable tar, with acetic acid, come 

 over, accompanied by the carbureted hydrogen gas. 

 The former of these products are condensed in the 

 worm, and run into a receiver. The gas escapes at an 

 aperture for the purpose, and is sometimes burnt, to il- 

 luminate the place. It would be advisable to let the 

 gas pass under a gasometer, in order to preserve it for 

 burning, and also to prevent the disagreeable smell 

 which accompanies the process. The gas furnished in 

 this process, is very similar to that furnished by the 

 distillation of coal. Indeed, there is some analogy in 

 the distillation of animal, vegetable, and mineral coal. 

 In the first, there is ammonia, and a substance having 

 •all the properties of tar, but much more fetid, owing to 

 the presence of sulphur, and probably phosphorus ; 

 there is also furnished an inflammable gas, which is 

 doubtless carbureted hydrogen mixed with other gases, 

 holding a portion of sulphur and phosphorus. 



In the distillation of wood there is no ammonia, but, 

 instead of it, acetic acid. The gas is similar, with the 

 exception of "the difference caused by the presence of 

 the sulphur and phosphorus. In the distillation of coal, 

 no acetic acid appears to be formed, but a small portion 

 of carbonate of ammonia : this would show it to be 

 more allied to the animal than the vegetable substance. 

 The gas furnished by coal, is principally the carbureted 

 hydrogen. It contains also a little sulphureted hydro- 

 gen, to absorb which, a portion of limewater is used 

 to pass the gas through, The distillation of coal, for 



the purposes of furnishing gas for the gas-lights, is at 

 present carried on with great advantage, the gas being 

 a valuable substitute for oil and tallow. The coak left 

 in the still, is superior to that made in the common way ; 

 and the tar might be used for many purposes, either in 

 the liquid form, or in the state of pitch, Which it as- 

 sumes by evaporation. The residuum from the wood 

 forms excellent charcoal. That from the bones of ani- 

 mals is generally ground down into powder, and sold 

 for ivory black. The coaly residuum from other ani- • 

 mal matter, such as hoofs and blood, is used for making 

 Prussian blue. In the distillation of any of these sub- 

 stances, it will be profitable to know, that if the retorts 

 or still, which is of cast iron, be allowed to cool every 

 day, that it will be soon destroyed by the oxygen of the 

 air ; but if it be constantly kept at work, by dischar- 

 ging and re-charging it without cooling, the vessels 

 will wear for several years. This will be found a valu- 

 able fact to those who have not yet adopted the plan. 



The only means of obtaining mercury in a state of Distillation 

 purity, particularly when it is alloyed with other me- °f mer- 

 tals, is by distillation. Nothing can answer better for cur y» 

 this purpose than an iron retort, having a long tube of 

 the same metal terminating over a vessel of water. The 

 mercury rises at 600° of Fahrenheit, so that a common 

 fire is quite sufficient for the process. 



The distillation of phosphorus is attended with more Distillation 

 difficulty than almost any other substance. The heat of phos- 

 required is considerably above that of a red heat. The phoms. 

 retort is required to be of earthen ware. If the sub- 

 stance of the retort be very open, the sublimed phospho- 

 rus escapes through it in the state of vapour. If the 

 substance of it be very close, it is in danger of breaking 

 in the bringing up. It is the best, therefore, to make 

 the body a little open, and cover the surface with flint 

 and borax to form a glazing, which prevents the vapour 

 of the phosphorus from escaping. The retort contain- 

 ing the charcoal and the phosphate of lead, should be 

 placed upon a stand in the middle of a small air fur- 

 nace, the neck passing through an opening in the side. 

 The end of the neck is firmly luted into a glass recei- 

 ver filled with azotic gas, from whence a small tube 

 passes into a pneumatic apparatus. The fire is raised 

 very gradually. Soon after the retort becomes red hot, 

 the phosphoric acid begins to be decomposed. A por- 

 tion of water is also decomposed at the same time. The 

 hydrogen unites to a portion of the phosphorus, form- 

 ing phosphoreted hydrogen gas, which passes through 

 the receiver into the pneumatic trough, along with a 

 large quantity of carbonic acid gas. Ultimately the phos- 

 phorus comes over, condenses in the neck of the retort, 

 and runs into the receiver, which contains a little water 

 for its reception. See Phosphorus under Chemistry. 



In most of the processes of distillation, particularly Lutes used 

 in the small way, substances called lutes are of great in distilla- 

 importance. When the heat is not much more than t ' ou - 

 boiling water, common flower paste, spread on linen 

 cloth, forms a good lute for uniting the joinings. Lin- 

 seed meal made into paste with water, is also used in 

 the same way. A paste, made with clay and oil, or 

 common glazier's putty, is very suitable when the heat 

 is not great, as in that case it becomes very soft. The 

 white of egg, or the serum of blood, or skimmed milk 

 made into a paste with lime, forms an excellent lute for 

 all temperatures under 300° of Fahrenheit. In the 

 distillation of oxymuriatic acid gas, bees- wax is some- 

 times used, but plaster of Paris is much better. This 

 answers very well in the distilling of nitric acid, as it 

 has no action upon it. When the joining is between two 



