f Vffful Nctlcts fffprltlng various OhjeStt. 



But becaufe the calcareous earth is combined partly with the fulphuric acid and partly 

 with the carbonic acid, it ibllows that the combination of the lapis is 



Gr^iins. 



Silex _ _ — ^5 ■ 



Alumine — — — '4-50 



Calcareous carbonate — — 28 



Calcareous fulphate — — 6.50 



Oxide of iron — — — 3 



Water — — — 2 . 



The fum is here complete, becaufe I have confidered the calcareous earth as perfcflly 

 faturatcd with the carbonic acid ; which does not however appear in fa£t to be the cafe. 



vr. 



Ufeful Notices rtfpeBing var'nus ObjeHs. — Rofe-Waier—Eait de Luce— Soap of Wool- 

 Sea Sicknefs. 



I. Roft-Water. 



A HE Gmple diftilled water from rofe-leaves, which is fold by the name of rofe-water, 

 has the difadvantage of lofing its fragrance, by a fpontaneous change which feems to be of 

 the nature of the putrid fermentation. This happens in much lefs time than mull elapfe 

 between the annual feafons when frefli rofe-leaves are to be had. The article is never- 

 thclefs to be purchafed at any time of the year ; from which circumftance it has been fup- 

 pofed that the manufacturing perfumers were in poflenion of fome method of preventing 

 the procefs by which it is changed. A philofophical friend alTures me that this is not the 

 cafe, but that they diftil only fo much rofe-water at a time as they know will keep during 

 the period of the regular demand for that quantity ; at the end of which they diftil the 

 fame quantity from other rofe-leaves. Their management for infuring a regular /upply 

 confids in packing the frefh rofe-leaves with common Hilt in a mafs, to a portion of which, 

 «'hen required, tliey add water, and diflil from the mixture. 



2. Eau dc Lnce, 



THE fame intelligent friend informs me, that the ufual recipes in the London Pharma- 

 copoeia and other books, for making the fragrant alkaline liquor called cau de luce, the lead- 

 ing perfection of which is, that it fhall poflefs and retain a milky opacity, do not fiiccccd, 

 but that a feparation takes place, and the fluid becomes more o? lefs clear by keeping. 

 The ufe of maftic in this compofition has hitherto been kept a fecret. Upon his afl'urancc 

 tliat tills is the chief ingredient, I made the following trials. One dram of the reQiiied 

 oil of amber was difTolvcd in four ounces of the flrongeft ardent fpirit of the (hops ; its 

 fpecific gravity being .840 at 60 degrees of Fahrenheit. This is the oily fpirit which is to 

 be added to volatile alkali to form eau de luce, according to Macquer, in his Didlionary, 

 who fpcaks highly of a recipe to this efTeil, but with the addition of ten or twelve grains 

 of white foap to the fpirit, previous to the oil. The purpofcs of my experiment did not 

 require the foap. A portion of the clear fpirit was poured upon a larger quantity of fine 

 3 powdered 



