g75 LUMINOUS BOTTLfi 



3. The alkaline folution, made by two lb. alkali to three Ir>« 

 water, cryftallizes too quick, and before the precipitation of 

 the file*. 



4. The dofes of alkali and water moft favourable to a regu- 

 lar cryftallization, at the temperature of from 5 to 10 above O 

 pf Reaumur, are one part of diftilled water, and half a part 

 of purified potato. 



If the refults of my experiments {hall improve the prepara- 

 tion of carbonate of potafh, and if the difpofition of my appa- 

 ratus prevents the neceffity of continually watching its direc- 

 tion, by procuring without trouble that gentle and continued 

 preflure, of which Pelletier perceived the efficacy for thefatu^ 

 ration of the alkali, I have reafbn to think that the true friends 

 of chemiftry, I mean thofe who pra&ife it, will confider m^ 

 pbfervations with indulgence. 



tea ■ ■,■" .'.,■' ',, "■ .::,. , ,, ,..•.' ,\. &..J,, ■,. .,:&. 



XVI. 



Method of preparing a luminous Bottle, which long prefcrves its 

 Effect* 



A luminous IT is eafy to prepare a bottle which fiiall give fufficient light 

 bottle. # Put 3 during the night to admit of the hour being eafily feen on the 

 phofphorus in a clial of a watch, as well as other objects, by the following. 



i°n?t P bailin 'ST mCanS ' 



The fluid will A phial of clear white glafs, of a long form, fljould be 

 give light in the c hofen, and fome fine olive oil fliould be heated to ebullition 

 whenever the m another veflel : A bit of phofphorus, of the fize of a pea, 

 coik is pulled mould be thrown into the phial, and the boiling oil mould 

 then be carefully poured over it, till the phial is one-third 

 filled : The phial mould then be carefully corked; and, when 

 it is to be ufed, it mould be unftopped, to admit the external 

 air, and clofed again : The empty fpace of the phial will 

 then appear luminous, and give as much light as a dull ordi- 

 nary lamp. Each time that the light difappears, on removing 

 the ftopper it will inftanlly re-appear. It is proper to ob» 

 ferve, that in cold weather it will be necefTary to warm the 

 bottle for a little while in the hands before the fropper is re- 

 moved, without which precaution it would not yield any light, 



* Sonini's Journal, 



A phial 



