ROBES, MASTER OF Till: 



HOCKET. 



140 



( making it hfe own. Rapina only differed from Furtum in being 



rmfcia WM eomiuittod in various ways, beside* by taking another 

 m*MT ptoperty. A debtor committed fnrtiiiii. if he fraudulently 

 carried off a thing which he had pledged to hit creditor. It was f urtuui 

 to nee a thing that had been lent, (or a different purpose from that for 

 wtueh it had been l.-nt. Ktirtum was either tuanifertum or nee maiii- 

 tatam. It wa* furtuin manifeetum beyond all doubt when the thief 

 WM caught in the act ; but then wai a difference of opinion an to 

 whether it wa furtuin manifeatum or nee luanifratiim in a variety . i 

 r**e According to ome writer*, it was fitrtum manifeatum if the 

 thief wai taken with the thing before he had reached the place to 

 which he intended to carry it Purtum which wai not manifestum 

 wo MO maniferturn. The Twelve Tablee made the punishment of 

 furtun manifMtum a capital offence, that in, an offence the penalty for 

 which affccted a person's caput or status. The edict changed this into 

 an aetio quadrupli. The remedy in the caw of f urtiim nee raanifeetum, 

 whkh the Twelve Tables nave, wan an actio dnpli. which il. 

 retained. All pamoi could bare the actio furti who had an interest 

 hi Ike preservation of the stolen thing ; consequently othen besides 



rfc lal < nd - i ton 



the owner could not bring it, an in the COM of bailment, provided the 

 bailee WM a responsible person. If he waa a responsible person, he 

 WM bound to mace good the loa* to the owner, and comtequently could 



lemn .' D : ia lotto 

 furti wan followed by infamia. 



Tli<- owner of the thing might also bring his action for the recovery 

 of the thing it*elf or iU value. 



The law of the Twelve Tables permitted a person to kill a thief who 

 WM detected in the act of theft in the night ; and a thief might be 

 killed in the day-time, if he defended himself with any weapon 

 (telunA But the severity of the old civil law was gradually niiii 

 gated by the edict, and the offence of theft was, as already observed, 

 only punishable by an action of furtum, and the consequent pecuniary 



Jtiea. 



The Roman law of Furtum is stated in Qaiug, iii. 183-209 ; Di'j., 47, 

 /*.. 4, tit. 1. 



R01 .KROFTHE.an officer of the household who has 



the ordering of the king'* robes. By statute 51 Henry III., the 

 " Gardein de la Qarderobe de Roi," the warden of the king's wardrobe, 

 was to make accompt yearly in the Exchequer, on the feast of 

 8t Margaret. The office lias always been one of great dignity. A 

 female sovereign has a mistress of the robes. High privileges were con- 

 ferred upon the office by King Henry VI., and others by King James I., 

 who erected the office of master of the robes into a corporation. 



KOUINIC ACID. An acid of doubtful composition, said to be 

 contained in the root of the JiMnia pxudo-acacia. It is crystalline 

 and deliquesces in moist air. 



HOCCKLLIC ACID, <C,.H M O.J) obtained from the SocceUa 

 tnHoria. This acid crystallines in fine colourless needles of a silky 

 lustre. It is insoluble in water, whether cold or hot ; alcohol dis- 

 aolre* it readily, 100 parts of 0-819 density, at the boiling-point. 

 taking up 56 parts. Ether also dissolves it easily : it melts at 266, 

 and solidifies at 261. 



The alkaline rocccllates dissolve in water, and yield solutions which 

 froth like soap ; but when concentrated, the solutions cannot be drawn 

 out in threads like those of other soaps. Rocccllate of potash crystal- 

 lise* in small lamina ; the salt of lime is a white precipitate, insoluble 

 in water, and contains 1.V9 per cent, of base. 



i:U.lNl.\. [LtCHESS, COLOPRIKO MATTERS OF.1 



!>< 'II U.I. K SALT. [TAHTAHIC Atml 

 !!'< K AI.I'M. [ALi'M.] 



it CRYSTAL,, [SILICON.] 

 ROCK SALT. [SoDit-M.) 



ICK-WORK, in gardening, an elevation, composed of earth and 



other loose materials, and covered with stones and fragments of rock, 



s.. amongst which plant* adapted for such a situation are grown. 



When the rock-work is managed skilfully, and in accordance with 



surrounding objects, it may be made to add much to the beauty and 



inteiest of the garden. In the first place a proper situation should 



' ' ! : ' : - Doutthi i:.' oi i witt the 



situation. Bhnph) outlines and surfaces not broken into fantastic 

 shapes, are best suited to show ofi' the plants. The best stones for 

 rock-work are those which resist the action of the air, and they may 

 be selected according to convenience from the rocks of the neighbour- 

 hood in which they are used. The most irregular ought to be . . 

 epecially tnone with cavities in them, which may be filled with earth 

 the growth of moates, ferns, and small pVin . IY< .pi. -ntly stones 

 are met with covered with lichens, v> I their picturesque 



colours, have a pleasing effect. Of these, the / 



pHinu. tn.fo.iu, perrlliu, and ultHarit, arc most common.' Such stones 

 are mostly large, and are best adapted for the base of the rock- 

 though rock-work is intended to present a mountainous in 



r ?!*?* n 5. to * "t** 1 * ftce> y* there "* man y circumstances that 

 be growth of true mountain and rock plants in such a situa- 

 tion ; but the dry ridge* of earth and stones of which it is composed 

 umd a favourable iitiiati..u fur the plant* that chiefly occupy the dry 



soil of plains. On this account, small shrubs and creeping plants of 

 any kind that will grow in a dry soil are selected for rook-work. Of 

 these, the varieties are numerous, and the taste and care of the culti- 

 vator may be advantageously shown in the selection. 



ROCKET is a cylindrical vessel or case, of pasteboard or metal, 

 attached to one end of a light rod of wood, and containing a compo- 

 sition whirh, being fired, the vessel and rod are projected through the 

 air by a force arising from the combustion. 



Rockets have long been used as a means of making signals for the 

 purpose of communication when the parties have been invisible from 

 distance or darkness, or otherwise inaccessible to each other ; and they 

 have occasionally served the important purpose of determining the 

 difference of longitude between two places. In the latter case the 

 rocket is fired at some convenient spot between the stations, from both 

 of which the explosion must be visible; and the latter being n.;ulv 

 instantaneous, the difference between the times at which it is observed, 

 as indicated by chronometers regulated so as to show the mean times 

 at the places, is the required difference of longitude. Kockct 

 also been constructed for the purpose of being used in warfare, and 

 such missiles were so employed for the first time at the siege of Copen- 

 hagen in 1807. 



In signal rockets the part of the case which contains the composition, 

 by whose combustion the projectile force is produced, is joined, at the 

 upper extremity, to a conical case containing the composition for pro- 

 ducing the explosions or stars of light which constitute the signal, and 

 the length of this part is always rather greater than the diameter of 

 the cylindrical part of the case. Such rockets are made to weigh half a 

 pound, one pound, or occasionally even two pounds. The exterior diameter 

 of the one-pound rocket is 1| inch; the length of the cylindrical case is 

 12$ inches, and the length of the conical head is 3J inches. The rod is 

 generally attached near the base and on one side of the rocket ; its 

 length is about 8 feet, or 60 diameters of the rocket, and its thickness 

 is about half a diameter of the latter. The composition with which 

 the cylinder is filled consists generally of saltpetre, sulphur, and charcoal 

 or gunpowder ; the whole is reduced to a mealed state, and well mixed 

 together in the following proportions : saltpetre, 4 Ibs. ; sulphur, 

 1 Ib. ; and charcoal, 1 Ib. 8 oz. The composition which produces what 

 are called the stars consists of saltpetre, 8 Ibs. ; sulphur, 2 Ibs. ; sulphide 

 of antimony, 2 Ibs. ; mealed powder, 8 oz. ; and isinglass, 3 j oz. The 

 latter is dissolved in one quart of vinegar, after which one pint of 

 spirit of wine is added, and then the mealed composition is mixed 

 with the liquid till the whole becomes of the same consistency as a stiff 

 paste. It is then moulded into short cylinders, and when dry, these 

 cylinders are packed into the head with a small bursting charge. 

 When the composition of the rocket is burnt out, the burster blows 

 open the head and frees the lighted stars. 



The rocket case having been placed on a conical spindle, which passes 

 a certain distance up the centre, the composition for burning is rammed 

 or driven round it, so that iu the interior about the axis a void space of 

 a conical form is left in order that a considerable surface of the com- 

 position may be at once in a state of combustion. The neck of the 

 rocket (the part to which the rod is attached), is then choked, or 

 reduced in size, leaving a small hole or vent through which the lire is 

 communicated to the composition. The combustion of the latter 

 immediately takes place on all the concave conical surface about the 

 void space just mentioned. 



In order to understand the cause of the rocket's motion, let it be 

 observed, that if the composition were to be fired within a vc 

 case closed on all sides, the pressure of the gas generated would be 

 equal in every direction, and the case would either burst in pieces, or, 

 if sufficiently strong, would remain at rest while all the composition 

 was being consumed. But, the case having an aperture or apertures 

 at the choke or lower extremity of the cylinder, the pressure which 

 would have taken place against that extremity is reduced by the escape 

 of the gas into the atmosphere ; and there is an excess of pressure on 

 the head, which is not counteracted by a pressure on the other ex- 

 tremity, equal in amount to the pressure due to a surface of the size 

 of the orifice, that is, disregarding the resistance of the atmosphere to 

 the escape of gas; and this pressure impels the rocket forwards or 

 ujiwanls. This force acta in a manner similar to that by which a gun 

 recoils when the charge is fired; but, in the latter case, the liui 1 

 escaping almost instantly from the bore, the force is one of impulse on 

 the bottom of the chamber which ceases nearly as soon as it is generated'; 

 whereas, in a rocket, the composition continuing to burn during !. 

 seconds, the force of impulse becomes a force of pressure, which con- 

 tinues to act till the material is consumed. Hence it follows that a 

 rocket ascends, or moves forward, with an accelerated motion till the 

 resistance of the air becomes equal to the accelerative force : and 

 when the composition is burnt out, the rocket falls to the ground. 

 We see then that cteterie paribus, the larger the vent or aperture, the 

 greater will be the pressure on the head, driving the rocket forward. 

 But this is modified by the consideration that the smaller the aperture 

 the greater will be the condensation, and, therefore, pressure of gas 

 generated ; or, in fact, that the gas should not be allowed to escape as 

 fast as it is generated. Again, the more rapidly the gas is generated, 

 or the stronger the composition is, the greater will be tin 

 but at the same time, the sooner will it be burnt out, and the stronger 

 and heavier must be the case, These consideration.!* are most import- 



