BOHEIC ACID. 



BOILING OF LIQUIDS. 



248 



The principal librarians since the foundation by Sir Thomas Bodley, 

 have been, 1. Thomas James, fellow of New College, 1598 ; 2. John 

 Rouse, fellow of Oriel, 1620; 3. Thomas Barlow, fellow, afterwards 

 provost of Queen's, bishop of Lincoln, 1653 ; 4. Thomas Lockey, 

 student, and afterwards canon of Christ Church, 1660; 5. Thomas 

 Hyde, of Queen's College, afterwards Laudian professor of Arabic, 

 regius professor of Hebrew, and canon of Christ Church, 1665 ; 6. John 

 Hudson, of Queen's, afterwards principal of St. Mary Hall, 1701 ; 7. 

 Joseph Bowles, fellow of Oriel, 1719; 8. Robert Fysher, fellow of 

 Oriel, 1726; 9. Humphrey Owen, fellow and afterwards principal of 

 Jesus College, 1747; 10. John Price, B.D., of Jesus College, afterwards 

 of Trinity, 1768; 11. Bulkeley Bandinel, D.D., late fellow of New 

 College, 1813, the present librarian. 



All members of the university who have taken a degree are admitted 

 to study in the library : no books have ever been suffered to be taken 

 from it. Literary persons, either native or foreign, are also allowed, 

 on being properly recommended, to read and take extracts from the 

 books in this collection. The library is open between Lady-day and 

 Michaelmas from nine in the morning till four in the afternoon ; and 

 during the other half-year from ten till three. It is closed on Sundays 

 and state holidays ; from Christmas-eve to the 1st of January inclu- 

 sively ; on the feast of the Epiphany ; from Good Friday to Easter 

 iy inclusively; on the days of Encrenia and Commemoration; 

 seven days immediately following the 1st of September, and eight days 

 preceding the visitation of the library, which takes place on the 1st of 

 November. On all other holidays it is opened immediately after the 

 university-sermon. 



''/i OB Bodleiance, Svo. London, 1703 ; Wood's Account of Bodley's 

 Library, JTitt. and Antiq. of t!ir I'nirersity ofO.rford, 4to. 1796, vol. ii. 

 P. ii. pp. 920-953 ; Chalmers's History of the Culleyes, Hall*, and Public 

 I'M attached to the Vnirergity of Orfard, vol. ii. pp. 458-464 ; 

 ' University and City Guide, 8vo. ; Parker's Hand-Hook for Ox- 

 ford ; and the Oxford University Calendar.) 



BOHEIC ACID. An astringent acid said to be contained in black 

 tea. Its existence is, however, very doubtfuL 

 BOHEMIANS. [GIPSIES.] 



BOIL, called also phlegmon and furunculus, from furo, to rage, on 

 account of the violence of the heat and inflammation attending it. A 

 boil-is a tumour of an inflammatory nature seated in the skin and in 

 the cellular tissue beneath it. It may occur on any part of the external 

 surface of the body, and it is of various sizes from the bulk of a pea to 

 that of a pigeon's egg, which latter it seldom exceeds. The tunnmr is 

 circumscribed, prominent, hard, of a conical figure, the base of the 

 i n'ing broad, deep, and intensely red. The whole surface of the 

 tumour is exquisitely tender, and is commonly attended with a very 

 painful sense of burning and throbbing. Its natural termination is in 

 suppuration, that is, in the formation of the matter called pus, but the 

 |in>gri*i) is always slow and the process itself imperfect, the pus formed 

 being generally scanty and never healthy. Only a few drops of puru- 

 lent matter, commonly mixed with blood, flow from the most prominent 

 or [lointed part of the tumour, while there remains behind the germ, or 

 what is commonly called the core, a purulent sloughy substance, so thick 

 and tenacious that] it appears like a solid body. When this core is 

 discharged, the pain entirely ceaaes and the opening heals spon- 

 taneously, but the removal of this is indispensable to the cure of the 

 disease. 



The complaint is never attended with danger, and seldom accom- 

 panied with fever, excepting when the tumour is seated over some 

 IKrciiliarly sensitive part, or when (as occasionally happens) several 

 tumours occur at the same time in several places. Under such circum- 

 stances, in adults of irritable habits, and almost always in children, a 

 good deal of constitutional disturbance is excited. 



The disease, though local in its seat, w constitutional in its origin, 

 nnd .-iffords a good example of a class of maladies, a very large one, 

 which ore limited in their seat to a small spot, perhaps on the external 

 Bin-face of the body, but which have their source in the disturbance of 

 omc internal organ or of the system in general 



The internal organ*, the derangement of which most commonly 

 produces this external disease, are thoee which belong either to the 

 digestive <>r to the excrernentitimis systems, or to both. In con- 

 sequence of the disordered state of these organs, either perfectly pure 

 chyle i* licit eliminated, or the blood is not properly depurated, or ex- 

 cremcntitioux matter is re-absorbed into it, the circulating iluiclH 

 become contaminated, ami the result is the irritation and inflammation 



surface. 



The rational and successful treatment of this disease must therefore 



combine two ol.jert-i, the removal of the local malady, ami the 



. cfcrrf" lered state of the system in which it has its 



' intention is accomplished by assisting the process of 



M, which, as already stated, is always tardy and imperfect, 



but must be reii' ]>'te before the malady can be removed. 



The prn]>er external applicatinx are repeated emollient poultices, as 



those made of linseed meal, which may be mixed, when the pain is 



violent, with conium, hyoscyamuH, or opium. The suppuration is so 



ini|;rfect that even the diligent use of poultices seldom causes the 



tumour t<> burst spontaneously with an aperture sufficiently large to 



allow of the discharge of the pus, together with the sloughy cellular 



substance that forma the core. As soon as any matter can be per- 



ceived in the tumour a free opening should therefore be made into it 

 with a lancet, and as much of the matter and slough as can be forced 

 out of it by tolerably firm pressure should be removed. 



While recourse is had to these external applications, it is indispens> 

 able to correct the disordered state of the organs. This may be 

 effected by a course of mild alterative medicines : the bowels should 

 always be freely opened at first, and then regulated by gentle unirri- 

 fcvting laxatives. At the same time strict attention should be paid to 

 the diet, which should be of the plainest and simplest nature, 

 nutritive but not stimulating, consisting of a moderate portion of 

 plainly cooked animal food, without fermented liquors, without pastry, 

 and without fruit. 



BOILER is the general name applied to vessels, whether close or 

 open, in which fluids are exposed to heat for the purpose of ebullition 

 or evaporation ; but the term is most commonly applied to the close 

 vessels used for the generation of steam. Such boilers, to lessen the 

 danger of explosion, are almost invariably made of wrought metal, 

 which, if burst, will tear rather than fly to pieces, as cast metal would 

 do ; and the plates made for the purpose are formed of the best and 

 toughest metal, and rolled or wrought with peculiar care. Engineer.; 

 differ as to the comparative merits of iron and copper as a material for 

 steam-engine boilers. Most however admit that iron, when of good 

 quality, has the greatest cohesive strength, although the greater uni- 

 formity of texture in sheet-copper renders it safe to construct copper 

 boilers of less thickness than those of iron, to withstand a given 

 pressure. Further than this, supposing an explosion to occur with a 

 copper boiler, it is likely only to produce a rent or tear in the metal, 

 while an iron boiler, even though wholly of wrought plates, is fre- 

 quently blown to pieces. The cost of copper is about four times that 

 of iron, but as, owing to its far more rapid transmission of heat, a 

 copper boiler may be made considerably smaller than an iron one to 

 produce the same quantity of steam, and may therefore be still further 

 reduced in thickness and weight without impairing its strength ; the 

 cost of a copper boiler is nearer twice than four times that of an iron 

 boiler of equal evaporating power ; and, as a set-off to this increased 

 expenditure, the value of the old copper, when the boiler is worn out, 

 is equal to three-fourths of its original cost, while an old iron boiler is 

 worth little more than the cost of removal. 



The various kinds of boiler employed in manufacturing operations 

 will be treated of under the heads of the different purposes for which 

 they are employed ; as STEAM-ENGINE, STEAM-CARRIAUE, STEAM-VESSEL, 

 SUOAB BOILING, WARMING AND VENTILATION, &c. 



BOILING OF LIQUIDS. A liquid is said to boil when bubbles of 

 the vapour of the liquid are formed, and, by reason of their lightness, 

 rise to its surface and escape. The circumstances conditioning the 

 formation of such bubbles are four : 1. The nature of the liquid in 

 respect to chemical constitution. 2. The temperature to which it is 

 exposed. 3. The pressure upon its surface, and consequently through- 

 out its mass. 4. The magnitude of the force of adhesion between the 

 liquid and the substance with which it is in contact. 



An example will illustrate this. A glass basin containing boiled 

 distilled water may be gradually heated to 216 Fahr. without the water 

 boiling. We have then the four above-named conditions in the following 

 state : 



1. Oxygen and hydrogen, in the proportion of 8 to 1 (HO), 



2. A temperature of 216 Fahr. 



3. The existing pressure of the atmosphere (say 15 Ibs. per square 

 inch). 



4. The adhesion between water and glass. 



By altering any one of these conditions, boiling or ebullition may be 

 produced. Thus : 1, if ether, (C^HjO)., be substituted for water, the 

 ether will boil ; 2 if, the temperature be raised a few degrees the water 

 will boil ; 3, if, the basin being put under the air-pump, the air be 

 exhausted, the pressure of the atmosphere being thereby diminished, 

 the water will boil ; 4, if the glass basin be replaced by a copper one, 

 the water will boil. 



Again, respecting the above-mentioned four conditions : 1, two or 

 more chemically dissimilar liquids may boil at the same temperature, 

 under the same pressure, and in the same vessels ; 2, one and the same 

 liquid cannot boil at two different temperatures under the same pres- 

 sure and in the same vessel ; 3, one and the same liquid cannot boil at 

 the same temperature under two different pressures in the same vessel ; 

 4, it is probable, although not certain, that one and the same liquid 

 cannot boil at the same temperature and under the some pressure in 

 two vessels whose internal surfaces so differ in texture or constitution 

 as to possess different adhesion to the liquid. But as both physical 

 texture and chemical constitution affect the boiling of a liquid inde- 

 pendently, it follows that the same liquid may boil at the same tempe- 

 rature and under the same pressure in vessels of unlike chemical 

 constitution, provided that their surfaces are so unlike in texture also 

 as to counterbalance their chemical dissimilarity. Thus, water boils at 

 a lower temperature in metallic vessels than in glass ones. It boila 

 also in vessels whose internal surfaces are rough at a lower temperature 

 than in smooth ones. Hence, in a smooth metallic vessel it may boil 

 at the same temperature and under the same pressure as it docs in a 

 rough glass one. 



We must examine one by one the above-mentioned four circum- 

 stances which determine the boiling of a liquid, bearing ia iniud that 



