On the Analjjts ofjl'lne: ^6^ 



not inclined in fuch a manner as to make the drops of the 

 liquid, which attach themfelves to them, trickle down into 

 the orutter which conveys them into the worm. I have found 

 by calculation that this inclination ought to be at leaft 75 de- 

 grees to the horizon. It is alfo neceirary that the water of 

 the refrigeratory ihould be frequently renev.-ed ; otherwife it 

 will foon acquire the temperature of the fleam, and be no 

 longer able to condenfe it. 



Though thefe principles in regard to diftillation are incon- 

 teftab]e,"fome modifications mud be made in ihem for the 

 purpofe of facilitating the operation : by giving to the aperture 

 of the boiler a diameter equal to that of the bafe, the capital 

 becomes verv wide; it i? confec]uenlly necefl'afy to give it 

 a confiderable height, that its fides may have the inclination 

 of 75 degrees. This confiniftion is attended with two great 

 inconveniences : the firft is, that it renders the capital heavy, 

 clumfv, and expenfi\e; the iccond, that it makes it difficult 

 to give to the upper edges of the boiler that ttrength neceflary 

 to withftand the effort of the capital. Thefe confiderations 

 induced me to make fome changes in the above conftruftion. 

 Thefe changes all relate to the form of the boiler : I make 

 the fides to project a little as they rife,, and then bring them 

 nearer to each other towards the top, in fuch a manner that 

 the diameter of the aperture may correfpond to that of the 

 bottom. This form removes the two effeii^s above mentioned, 

 and has the advantage of prefenting a border at the upper part, 

 againft which the bubbles arifing from too ttrong an ebullition 

 may be broken, and thrown back to the centre of the boiler. 



Befides this chanoe in the form of the boiler, I thought it 

 pniper to take away the refrigeratory with which the capital 

 was covered, and which was attended with the inconvenience 

 of coolinjr the fteam, and forming a cloud of vapour in the 

 infide, which oppofes its further afcenfion. 



It may be obferved, that in diliilling by means of a retort 

 in a fand-baih, it will be fufficient to apply a cool body to 

 the retort to produce this efl'etl : ftrije are immediately fecn 

 formed on the fides, and the liquor falb to the bottom of the 

 retort. 



If I at firft propofed to prcferve the refrigeratory, it was 

 bccaufe I afcribed to it a part of the eflefils which depended 

 on a proper confiruftion of the furnace. I, however, after- 

 wards found that a fiil! greater effect was obtained by fup- 

 prefling the refrigeratory. Befides, this change was more 

 economical, and occafioned lefs embarraflment. 



After this I conceived that the great art of condcnfing the 

 vapours was confined to enlarging the beak of the capital; 



Vol. XI. A a and 



