245 



PANTOGRAPH. 



PAPAVER. OPIUM. 



218 



not only to the beauty but to the utility of the drawing. The pencil 

 too, constantly working upright, does not maintain that fine point 

 which is required for distinctness of outline, and to these faults we 

 must add inaccuracy of workmanship, however slight, the effect of 

 wear, inequalities of the paper, and other accidents. 



The best way to tent an instrument is to reverse the position of the 

 tracer and pencil, thus producing a copy larger than the original, when 

 the defects will of course be exaggerated in proportion. 



The pantograph, however, though it cannot be depended upon for 

 an accurate and finished copy, is of great service to the draughtsman, 

 for by it may be marked off all the principal points through which to 

 draw the lines of a plan with equal accuracy and infinitely greater 

 facility than by any other means used for the purpose. 



The annexed engraving represents a pantograph which possesses 

 some advantages over that before described. In the first place, the 

 fulcrum being in the centre, it requires but one castor, which is placed 

 at c, and makes it work much lighter in hand than the old instrument, 

 which has six ; besides which these six castors are frequently a source 

 of annoyance by getting off the edge of the drawing-board and running 

 orer drawing-pins or anything else which may happen to be in the 

 way. Secondly, the shape of this instrument allows it to move as 



Fig, 



freely when nearly closed as when opened wide, which is not the case 

 with the other. " This improved instrument consists of six bars, 

 moving freely about each other at the six points of juncture, so 

 arranged with regard to length that A r and T B are always parallel to 

 each other. T is the fulcrum, furnished with a socket and screw (a), 

 through which the centre bar can be moved, and which can be fastened 

 down at any of the graduations on that bar. This socket, with the 

 bar, turns upon the pin rising out of the centre of the flat weight, as 

 shown in the diagram. Now the tracer T, the fulcrum T, and the 

 pencil P must always be in a straight line. To produce a copy the 

 same size as the original, the fulcrum must be in the centre, and the 

 pencil and tracer, as in the engraving, equi-distant from the centre* "f 

 their respective arms, and consequently from the fulcrum. For a half- 

 sized copy the pencil must be shifted half way up the arm to p, and 

 the fulcrum to /, in the straight line tfp, and so on for any required 

 proportion, which is apparent by a glance at the diagram. The rule 

 laid down in regard to the other instrument holds good for this, the 

 copy bearing the same proportion to the original as the distance of the 

 pencil from the fulcrum doe* to that of the tracer. 



In using the pantograph it is frequently necessary to copy the draw- 

 ing in divisions, on account of the instrument not being large enough 

 to extend over the whole surface at once. In this case the greatest 

 care is requisite to join the lines of one division accurately to those of 

 the adjoining division. The best way of effecting this is to hold the 

 tracer down upon a point in the original by one hand, moving the 

 fulcrum about with the other, until the pencil exactly coincides with 

 the corresponding point in the copy. To ensure accuracy, this should 

 be tried with three or more points, as the least deviation will throw 

 the whole plan out of position. 



In practice a large number of plans are copied of the same size as the 

 original. The quickest method, which, however, requires great care, 

 is to pin down a piece of tracing-paper upon the original, on which the 

 line* are marked with a fine-pointed pencil. A piece of ]per nibbed 

 over with blacklead is then placed upon the paper intended for the 

 copy, with the black side downwards, and the tracing-paper is pinned 

 down upon it; the lines then are carefully traced over with a steel 

 point, and the pressure transfers the blacklead to the drawing-paper 

 beneath. The black paper is sometimes omitted, and the lines, 

 traced by slight indentations only, are finished by hand, in the usual 

 mam 



If it is required to reduce a plan, and the draughtsman does not 

 possess a pantograph, the usual way is to divide the original and the 

 paper for the copy, whatever the relative size, into the same number 

 of squares, which will of course then bear the sune proportion to each 

 other as the surfaces of which they are divisions. The lines mult 

 then be set in singly, either by the assistance of tho proportional com- 

 pus or scale, or by a geometrical scale drawn for the occasion. The 

 following method is dependent only upon the compass and T square. 



Draw a triangle in which A B is the base, and make AC I.I-M- tiir 

 same proportion to c B as you wish the copy to bear to the original ; 

 take any distance on the original, and set it off from B on nc, draw a 

 line parallel to A B, and that portion of A c cut off by Mich parallel wi 



bear the required proportion to the distance set off on B c, aa may be 

 seen by the divisions 1 2 3 4 on the two sides of the triangle in the 



diagram. The triangle should be drawn in ink, and the distances, 

 being marked in pencil, may be nibbed out when transferred to the 

 paper. [EiDOGRAPH ; PROPORTIONAL COMPASSES.] 



PANTOMIME, the name of a species of dramatic performance in 

 which the actors express themselves by gestures. The name is com- 

 posed of two Greek words, meaning " imitation of every thing." 

 Pantomimic acting, accompanied by music, has been in use among the 

 Chinese, Persians, and other Oriental people from the oldest times. 

 The Greeks introduced the pantomime in their choruses, some of the 

 actors dancing and gesticulating, accompanied by music, whilst others 

 sang. (Lucian, ' De Saltatione.') The Romans had entire dramatic 

 representations consisting of dance and gestures only, styled " saltatio 

 pantomimorum," and some of their performers attained a high degree 

 of excellence in the art. Two of them, Bathyllns and Pylades, in the 

 time of Augustus, have been celebrated by the Roman writers. 



In modern times pantomimic balls, representing an entire dramatic 

 action or fable, have become a favourite scenic performance. The 

 Tuscan Angiolini, in the last century, and after him Vigan5, who died 

 at Milan in 1821, haveexcelled in this species of composition. Noverre, 

 in France, distinguished himself likewise in the composition of panto- 

 mimic " ballets." The name is now commonly applied to the harle- 

 quinade theatrical performances exhibited in London at Christmas and 

 Easter. 



(Meursius, Orchatra ; Signorelli, Storia Critica del Tcalri antic'ii e 

 moderni.) 



PAPA'VER. OPIUM, Medical Propertiei of. The juice of the 

 unripe capsule or fruit of the Paparcr tomniferum seems to have been 

 used on account of its narcotic powers from a very early period, first in 

 the East, of which it is a native, and afterwards in the West. 



As to the two varieties of the P. tomnifertim, called P. S. album, in 

 which the seeds are white, and the openings under the stigmata oblite- 

 rated, and P. R. wi'.-.rum, in which the seeds are blackish-gray, and the 

 openings under the stigmata perfect, some differences are found in the 

 relative proportion of some of the chemical constituents of the opium 

 procured from them ; but the P. S. album (Paparer ojficinale, Gmelin) 

 is the kind chiefly cultivated in Persia and India. 



" The first sophistication which the juice receives is that practised 

 by the peasants who collect it, and who lightly scrape the epidermis 

 from the shell to augment the weight. This operation adds about one- 

 twelfth of foreign matters. Thus collected, opium has the form of a 

 glutinous and granular jelly. It is deposited in small earthen vessels, 

 and beat up with saliva. On inquiring why water was not employed 

 in the place of saliva, the answer was, that water caused it to spoil. It 

 is afterwards enveloped in dry leaves, and in this state is sold. The 

 seeds of those poppies which have yielded opium are equally good for 

 sowing the following year." Such is the account by M. Ch. Texier, of 

 the plan in Asia Minor. A change of seed, however, by obtaining some 

 from a distant locality, seems expedient. (Dr. Eatwell, in ' Pharm. 

 Journal,' vols. xi. and xii., 1852.) In India, the juice is mixed with 

 oil obtained from the seed of the poppy, to hinder the rapid drying of 

 th<; juice. The produce of the first excisions is of a light yellow colour; 

 the others are fainter in odour and darker coloured. In general, all 

 three gatherings are mixed together, and sent to market in small 

 baskets. The quantity obtained varies not only with the soil and 

 mode of cultivation, but also with the season mid the time of collecting. 

 In wet gloomy seasons, not only is the quantity less, but it does not 

 keep well ; in such a case the proportion of morphia is also less. The 

 quantity of morphia depends likewise very much on the time of gather- 

 ing : if the harvest be postponed till the capsules begin to turn white and 

 hard, it is generally deficient, and by the time the capsules are mature 

 and the seeds ripe it has entirely disappeared. It is not, as is the case 

 of many other vegetable alkaloids, transferred to the seeds, as they are 

 altogether devoid of any narcotic principle, the oil which is obtained 

 from them being bland and wholesome, and abundantly used as food ; 

 even the seeds themselves are freely eaten by birds, to which they are 

 given (from the black variety) under the name of maw-seeds. In 

 India and Turkey they are made into comfits, or strewed over sweet- 

 meats, like carraway seeds. 



Several varieties of opium are met with in commerce, which may be 

 noticed here in the order of their reputed excellence, the quantity of 

 morphia contained in each being assumed as the criterion. 



1, Smyrna or l^rant opium, which Dr. Pereira considers syno- 

 nymous with Turkey opium, though German pharmacologists deem 

 Turkey and Egyptian opium to be synonymous. (Th. Martins, ' Phar- 

 makognosie.') " It occurs in irregular roundish or flattened masses of 



