R O S 



R O S 



contrivance is the figure of the veflel which receives the oil ; 

 this is made like an ordinary matrafs, from the lower part 

 of the belly of which comes a tube, as from an eld- 

 fafhioned cruet, and rifing to the bottom of the neck of the 

 receiver, it bends outward ; fo that though the veflel ufually 

 contains but two or three French pints, it conveniently 

 receives and lets pafs many hundred pints of the rofe-water, 

 without any necefiky of being changed ; for a change would 

 lofe the fmall quantity of the oil obtained. The water 

 diftilled runs through a pipe into a fecond receiver ; the oil, 

 being lighter than the water, floats upon its furface, and ad- 

 heres to the neck of the veflel, as high as the aperture of 

 the little pipe, while the water runs from the bottom of the 

 firft receiver into the fecond. See Mem. de l'Acad. des 

 Sciences, 1700. 



M. Homberg obferves, that this ftill may be ufeful to 

 draw off any kind of precious eflential oils. 



The procefs for making attar, or eflential oil of rofes, 

 fo much efteemed as a perfume, is related in the " Aliatic 

 Refearches," (vol. i. p. 332.) by lieutenant-colonel Polier, 

 and is as follows. " Forty pounds of frefh rofes, with their 

 calyces, but the Items cut clofe, are put in a ftill with 60 

 pounds of water. The inafs is then well mixed together 

 with the hands, and a gentle fire is made under the ftill. 

 When the water begins to grow hot, and fumes to rife, the 

 cap of the ftill is put on, and the pipe fixed ; the chinks 

 are then well luted with pafte, and cold water put on the re- 

 frigeratory at the top. The receiver is alfo adapted at the 

 end of the pipe ; and the fire is continued under the ftill, 

 neither too violent nor too weak. When the impregnated 

 water begins to come over, and the ftill is very hot, the fire 

 is lefiened by gentle degrees, and the diftillation continued 

 till thirty pounds of water are come over, which is generally 

 done in about four or five hours. This rofe-water is to be 

 poured again on a frefh quantity (forty pounds) of rofes ; 

 and from fifteen to twenty pounds of water are to be drawn 

 by diftillation, following the fame procefs as before. The 

 rofe-water thus made and cohobated, will be found, if the 

 rofes were good and frefh, and the diftillation carefully per- 

 formed, highly fcented with the rofes. It is then poured 

 into pans either of earthen-ware or of tinned metal, and left 

 expofed to the frefh air for the night. The altar, or ejfence, 

 will be found in the morning congealed, and fwimming on 

 the top of the water. This is to be carefully feparated, 

 and collected, either with a thin fhell or a fkirnmer, and 

 poured into a vial. When a certain quantity has thus been 

 obtained, the water and feces mull be feparated from the 

 clear efTence, which, with refpeft to the firft, will not be 

 difficult to do, as the efience congeals with a flight cold, and 

 the water may then be made to run off. If, after that, the 

 efience is kept fluid by heat, the feces will fubfide, and may 

 be feparated ; but if the operation has been neatly per- 

 formed, thefe will be little or none. The feces are as 

 highly perfumed as the efience, and muft be kept after as 

 much of the efTence has been fkimmed from the rofe-wafcr 

 as could be. The remaining water fhould be ufed for frefh 

 diftillations, inftead of common water ; at Ieaft as far as it 

 will go. 



" The above is the whole procefs of making genuine attar 

 of rofes. But, as the roles of this country give but a very 

 fmall quantity of efience, and it is in high efteem, various 

 ways have been thought of to augment the quantity, though 

 at the expence of the quality. In this country it is ufual 

 to add to the rofes, when put in the ftill, a quantity of 

 fandal-wood rafpings, fome more, fome lefs, from one to 

 five tolahs, or half ounces. The fandal contains a deal of 

 eflential oil, which comes over freely in the common diftilla- 



tion, and mixing with the rofe-water and efTence, become!* 

 flrongly impregnated with their perfume. The impofition, 

 however, cannot be concealed ; the eflential oil of fandal 

 will not congeal in common cold ; and its fmell cannot be 

 kept under, but will be apparent and predominate, in fpite 

 of every art. In Cafhemire they feldom ufe fandal to adul- 

 terate the attar ; but I have been informed, to increafe the 

 quantity, they diltil with the rofes a fweet-fcented grais, 

 which does not communicate any unpleafant fcent, and gives 

 the attar a high clear green colour. This efTence alfo does 

 not congeal in a flight cold, as that of rofes." 



The quantity of eifential oil to be obtained from the rofes 

 is very precarious, as it depends not only on the fkill of the 

 diftiller, but alio oh the quality of the rofes, and the fa- 

 vourablenefs of the feafon. In order to obtain 4 mafhas 

 (about 1 5 drachm) from 80 pounds, which, deducting the 

 calyces, amounts to fomething lefs than 3 drachms per 100 

 pounds of rofe-leaves, the feafon muft be very favourable, 

 and the operation carefully performed. The colour of the 

 attar of rofes is no criterion of its goodnefs, quality, or 

 country. In the year 1787, Col. Polier had attar of a fine 

 emerald green, of a bright yellow, and of a reddifh hue, 

 from the fame ground, and obtained by the fame procefs, 

 only of rofes collected at different days. The calyces, he 

 obferves, do not in any degree diminifh the quality of the 

 attar, nor impart any green colour to it ; though perhaps 

 they may augment the quantity ; but the trouble neceffary 

 for ftripping them muft, and ought, to prevent its being 

 ever put in practice. 



Roses, Oil of. See Rose, and the preceding article. 



RosE-jp/y, in Natural Hijlory, the name given by authors 

 to a peculiar fpecies of fly, found very frequent on rofe- 

 bufhes, and produced out of a baftard caterpillar, which 

 feeds on the leaves of that tree. See Cynips. 



The male of this fly has a long body, the female a fhort 

 and thick one ; fhe depofits her eggs in fmall holes, which 

 fhe makes in the bark of the young branches, and for this 

 purpofe is furnifhed with a very remarkable initrument, 

 placed at the hinder part of the body, which is a kind of 

 faw. 



This is a four-winged fly, and is fo common on rofe- 

 bufhes, that it is fcarcely poflible to mifs it in any of the 

 fummer months ; and the parts of the branches where it has 

 depofited its eggs are fo vitiated by it, that they alfo are 

 eafily known. They are ufually fwelled to a greater bignefs 

 than either the part above or below them, and are ufually 

 fomewhat bent ; they are often black on the under fide, and 

 among this blacknefs the holes made for the eggs, and often 

 the eggs in them, may be feen. The head and breaft of this 

 fly are black ; its wing's alfo are edged with black, its body 

 is yellow, and its legs yellow, with a few black fpots. 



If thefe flies be obferved in a fummer morning, as they 

 are crawling on the branches of a rofe-tree, they will foon 

 be found at work for the depofiting of their eggs. Thefe 

 creatures give us a very good opportunity of obferving the 

 manner in which they perform this, as they are of a very 

 fluggifh difpofition, and will ftand ftill even to be taken 

 between the fingers ; fo that when one of them is in a 

 proper fituation, it may be examined by bringing the eye 

 near it, and by afing the common magnifying glafles, with- 

 out quitting its place or its work ; and if there be leaves of 

 the tree, or fmall branches of it in the way, they may be 

 removed without difturbing the creature. Reaumur's Hilt. 

 Inf. vol. ix. p. 145. 



There is, befides this fpecies, another fly of the fame 

 genus, produced from a baftard caterpillar of the rofe-tree, 

 and of the fame fliape and ftrufture of parts with this, but 



different 



