BAR 



295 



BAR 



Fahren- 

 heit's pa- 

 rameter. 



fa 'well 's 

 barometer. 

 Plate 

 LIIL 

 Jig. 13. 



Barometer, which is more dense ; on the other hand, if the air 



Baron. becomes lighter, a contrary effect will happen. This 



' barometer, is oLn.Jiisly founded on the hydrostatical 



principle, that a body suspended in a fluid loses as 



much of its weight, as is equal to the weight of the 



fluid displaced. Phil. Trans. 1666. No. 14. 



Fahrenheit proposed a barometer, founded, in 

 principle, on the well-known fact, that the boiling 

 point of liquids varies with the pressure on their sur- 

 face. If a thermometer be taken with a large bulb, 

 and a small bore, and the boiling points of water be 

 marked upon it, corresponding to the various heights 

 of the mercury in the Torricellian tube at the time 

 of observation, the divisions on the thermometer will 

 indicate the pressure of the air, when the instrument 

 is afterwards plunged into boiling water. The range 

 of the scale, however, would be very limited ; as a 

 change of atmospherical pressure, causing a descent 

 of one inch tof the mercury in the barometer, depres- 

 ses the boiling point of water only \\ degrees ; the 

 instrument would also be troublesome in application. 



In the Philosophical Transactions, a barometer of 

 the following construction is described by Mr Cas- 

 well : ABCD is a vessel filled with water, in which 

 is immersed the barometer msoyzerx, consisting of 

 a body msoerx, and two tubes ex and 01/ze. The 

 body and the lower tube are hollow cylinders, and 

 communicate with each other. The lower extremity 

 of the tubeyz has a weight affixed to it, to make 

 the instrument sink, so that the top of the body may 

 just swim even with the surface of the water, by the 

 addition of necessary weights on the top. When the 

 instrument is forced with its mouth downwards, the 

 water ascends up into the tube to the height ut ; and 

 the small concave cylinder ex at the top gives buoy- 

 ancy to the whole, and prevents the instrument from 

 sinking below the proper depth ; md is a wire ; and 

 mS and cd are two threads stretched obliquely to the 

 surface of the water, in order to increase the range 

 of the scale. An alteration of the gravity of the air 

 causes the instrument to subside more or less ; and a 

 small bubble is formed where the surface of the wa- 

 ter cuts the threads, which ascends and descends 

 along them, as the mercury ascends and descends in 

 the common barometer. This instrument is much 

 commended by its inventor for its extreme delicacy ; 

 but the difficulty of applying an accurate scale to it, 

 renders it of little value. 



On the whole, it may be remarked, that the prin- 

 ciple of the Torricellian experiment affords the best 

 method of constructing the barometer with accuracy ; 

 particularly as, by means of a vernier scale, the height 

 of the mercury may be readily determined to the 

 thousandth part of an inch ; a degree of correctness 

 sufficient for every scientific and practical purpose, 

 and which cannot be obtained with certainty by con- 

 structions of a more complicaied nature. 



The references to works on the subject of baro- 

 meters will be given with more propriety under the 

 articles Height:, and Mkteokoi.ogy. (a) 



B/ 1 RON, a distinguished person, originally hold- 

 ing a barony ; and now either holding a barony, or 

 capable, by letters patent, of sitting and voting in 

 the upper house of parliament. 



Etymologists are not agreed with repect to the de- 



rivation and primary meaning of this term. The 

 most probable account of it is, that the word baron is 

 of German or perhaps of Celtic extraction, and that, 

 in the language of those who first employed it, it 

 was synonymous with man in general. It has this 

 meaning in the Salic law, and in the laws of the Lom- 

 bards ; Philomcnes renders it by >;;, and in the Eng- 

 lish law, the phrase " baron and feme" is equivalent 

 to that of man and wife. Retaining its general sense. 

 it appears next to have been used, either in bonat 

 or i,i malum partem ; iu the former, as when it wai 

 employed to denote a man of respectability, (ansg, 

 vir,) a stout or valiant man, and in the latter, as 

 when barone is used by the Italians, to signify a beg- 

 gar. From denoting a stout or valiant man, it was 

 employed xT s|o>;v as a name for a distinguished mi- 

 litary leader ; and particularly for one of those cap- 

 tains, who, having fought and conquered under some 

 great commander, were afterwards rewarded by him 

 with a part of the lands which he had acquired. This 

 part became the property of tire new possessor, and" 

 descended to his heirs, on condition of military ser- 

 vice ; understanding by these words assistance in the 

 formation and direction, as well as in the execution 

 of military schemes. Such was the import of the 

 term baron, when the feudal system was established, 

 and while its earliest institutions continued in their 

 vigour ; but changes having taken place in the state 

 of society, and the feudal institutes having been modi- 

 fied or abolished, it gradually acquired the meaning 

 which we have attempted to express in the definition 

 at the beginning of this article. As explanatory of 

 that definition, it may here be added, that, in reference 

 to those who are capable of sitting and voting in the 

 upper house of parliament, the word baron is used 

 with a certain variety of signification. Thus, in a ge- 

 neral sense, all noblemen are barons; as when we say, 

 that the Duke of Norfolk is, with the exception of 

 the blood royal, the first baron of England, or that 

 the Duke of Hamilton is, with the same exception, 

 the first baron of Scotland ; but, in a sense more li- 

 mited and appropriate, he only is a baron who has 

 rank and place immediately after a viscount. 



In the history of most European countries, the ba- 

 rons are represented, either as feudal lords, in pos- 

 session of a certain authority over their vassals, and 

 of certain benefits resulting from that authority ; or, 

 as the chief officers and functionaries of the crown, 

 summoned by the monarch, as occasion required, to 

 assist him with their advice, and attend him in his 

 expeditions ; and contributing to the dignity, as well 

 as the efficacy, of his government, in a way similar to 

 that in which their own vassals were bound to sup- 

 port them in their own individual capacity. They 

 are to be viewed either as masters or as servants ; as 

 masters, with respect to those who acknowledged 

 their feudal jurisdiction ; and as servants, with respect 

 to the king, whose ministers and dependants they, 

 were. See Feudal System. 



When we consider them as feudal superiors, we 

 perceive them exercising many of the rights, and en- 

 joying many of the privileges, which are now exclu- 

 sively attached to royalty. Thus we find them de- 

 claring war and making peace ; issuing from their 

 castles at the head of their retainers, harassing each 



biroii. 



