October 1, 1898.] 



KNOWLEDGE 



237 



to pay even for the ground upon -which they are grown. 

 The orange is one of the most wholesome fruits known, 

 and a truly valuable refrigerant, and it is remarkable that 

 very few people dislike the orange. Besides the use of the 

 pulp as au edible, the rind of the fruit, known as sweet 

 orange peel, is valued for its aromatic, stimulant, and 

 slightly tonic properties. The essential oil contained in 

 such large quantities in the glands of the rind is extracted 

 in the South of France and at Messina both by the sponge 

 and ecuelle processes, which will be more fully described 

 when considering the lemon. Large quantities of oil of ! 

 orange peel are used in Germany in the preparation of 1 

 perfumes and liqueurs. 



From the flowers a volatile oil is distilled, known as oil I 

 of neroli, which is one of the mgredients in Eau de Cologne, I 

 and is also used in perfumery and liqueurs. Besides this, 

 the leaves and young shoots of the orange plant yield by 

 distillation another kind of oil known as Essem-e -If pHit 

 grain. The bitter or Seville orange, which is a variety of 

 the last named, is rather a smaller tree, and does not 

 seem to be cultivated in India except in gardens, but it is 

 extensively grown in the same countries as the sweet 

 orange. The chief distinction is that the rind of the fruit 

 has a bitter aromatic taste. It is used in making candied 

 orange peel. The flowers are also used in distilling for 

 oil of neroli. This variety, which is now classified as ( 'itnis 

 Auriintium, var. Biycirndia, was at one time considered 

 a distinct species under the name of C. vuhiaris. The 

 Bergamotte orange is another variety (C. Aunintium, var. 

 lit'ni(imia). Its chief distinctions from the sweet orange 

 are its smaller flowers, which are known by their delicate 

 and peculiar odour, and the paler colour of the fruit. The 

 Bergamotte orange is grown chiefly near Reggio, in 

 Southern Calabria, and more sparingly in Sicily, Southern 

 France, and elsewhere. The volatile oil obtained from 

 the rind of the fruit forms the Essence of Bergamot of the 

 chemist, the principal use of which is in perfumery, while 

 from the pulp is obtained, by expression, the acid juice 

 which forms a portion of the commercial lime-juice. 



Citrus mcdica is the tree that produces the citron fruits. 

 The plant does not exceed ten or twelve feet in height, 

 and, like the species before mentioned, is not known in a 

 truly wild state. It is, however, to Northern India that it 

 is supposed to belong, and to have spread westward at a 

 very early period, being cultivated in Syria in the time of 

 Josephus, and probably introduced into Italy in the third 

 century, from whence it spread through the Mediterranean 

 regions. Its cultivation at the present time is chiefly 

 carried on in the neighbourhood of Florence, in Sicily, 

 Corsica, and the Riviera, and to a smaller extent in the 

 Azores, Madeira, India, and China. Citron fruits are 

 mostly of very large size, sometimes weighing several 

 poixnds, and measuring eight or nine inches in length, and 

 four or five in diameter. It has a thick rind and a very 

 small proportion of pulp. The rind is much used for 

 making candied citron peel for dessert or confectionery 

 purposes. Like all the orange tribe the rind is filled with 

 oil glands, which is extracted in the same way as is lemon 

 oil or essence, next to be described. Citron essence or oil, 

 usually known as essence of cedrat, is much valued in 

 perfumery on account of its agreeable odour. C. meilica, 

 var. Limonum, is the lemon, which is a straggling bush or 

 small tree, ten to twelve feet high. Under cultivation it 

 is now found throughout the Mediterranean region, and 

 in all tropical and sub-tropical countries. It seems to 

 have made its first appearance in Europe about the 

 latter part of the fifteenth century. Lemons come to this 

 country from Southern Europe, principally from Sicily, 

 but also from Spain, packed in boxes or chests, and, like 



oranges, wrapped separately in paper. Lemon peel is 

 candied in the same way as citron when it is used in con- 

 fectionery and for culinary purposes. The dried peel is 

 used in medicine. In its fresh state lemon peel is studded 

 with numerous receptacles filled with a very fragrant 

 volatile oil, which, when expressed and purified, is known 

 as oil or essence of lemon. For expression two processes 

 are employed, one known as the ecuelle and the other 

 as the sponge process. For the purpose of expressing, 

 or distillation — for some oil of an inferior quality is 

 obtained in this manner — only the small or irregular 

 fruits are used, the best shaped being selected for exporta- 

 tion. The fruits are gathered before they are quite ripe, 

 as the oil is of a better quality than when they are 

 fully matured. The peel is first cut ott' by the workman 

 in three longitudinal pieces, and the portion containing 

 the pulp is placed on one side. On the following day 

 the pieces of peel are operated upon in the following 

 manner : the workman takes the ecnelle, which consists 

 of a shallow basin-like funnel, the spout portion 

 of which is closed at the bottom, the inside of 

 the basin is studded with sharp points against which 

 the rind is pressed by the workman, this ruptures 

 the oil vessels, and the oil trickles into the closed spout, 

 which, when full, is emptied into another vessel. The 

 sponge process is practically the same, except that in 

 place of an ecuelle a sponge is used, which becomes 

 saturated with the oil and when full is squeezed out. 

 Prepared by either process, oil of lemon is of a light 

 yellow colour, and has a very fragrant odour. It is 

 mostly exported in small cylindrical coppers. Lemon 

 juice is the concentrated acid juice of the pulp, which, 

 together with that of the bergamot and lime, are the 

 bases from which citric acid is made. 



The acid lime, from which the bulk of the lime juice 

 is now obtained in the West Indies, is the fruit of 

 Citrm mi'dira, var. nciila, while the sweet lime is from 

 ( '. iiieilica, var. Limetta. 



NOTES ON COMETS AND METEORS. 



By W. F. Denning, f.r.a.s. 



Perrine's Comet (1898. I.). — Elliptical elements have 

 been computed for this object by Ilerr K. Pokrowskij from 

 observations between March 21 and May 21, and he finds 

 the period three hundred and twenty-two and a-half 

 years. This comet is possibly still perceptible in powerful 

 telescopes, and is moving very slowly westwards, in the 

 western part of the Lynx, its place on October 11th being 

 R.A. 6h. 24m. 59s., Dec. -f50^ 24-8', and on October 19th, 

 R.A. 6h. IGm. 53s., Dec. +50° 17-1'. 



Wolf's Co:^iet continues visible, though it is a decidedly 

 faint object. It is situated in Monoceros, and at the 

 beginning of October will be at a distance of about one 

 hundred and forty-five millions of miles from the earth. 

 Its position on October 1st will be R.A. 6h. 39m. 283., 

 Dec. -f 3° 33-2'. 



Encke's Comet, and the comets of Perrine and Cod- 

 dington discovered in June are too far south for observations 

 in this country. (Hacobini's comet is probably too faint 

 to be seen in ordinary instruments. 



The Perseids of 1898 certainly formed a stronger shower 

 than usual, and appear to have been very generally 

 observed. M. C. Flammarion reports that on August 10th 

 from lOh. to llh. HOm. they were watched from the 

 observatory at Juvisy, and that five hundred meteors were 

 registered and marked down on a map of the heavens. 

 At the Paris observatory Mile. Elumpe observed two 



