Overflowing Well. — Sctentifle Newt, Vf^ 



in giving you this defcription of it } and have the honour of being with the greateft re- 

 gard, &C. &C. B» VULLIAMVr 



Explanation of Plate XIL- 



■ Fig. r. ■ . 



a Top of the welJj with the water running ove*» 

 -bb Ground line-. 

 c Sand lying in the well. 



d Copper pipe. , 



ffffff Steining of the welf. 



^1^ Double fteining fix feet from the bottom upward's, 

 h Stratum which the end of the copper pipe was driven inta» 

 Fig. II and III. 

 Iron box for drawing fand out of the well, weighing about 6olbs, one foot fquare, and 

 two feet nine inches long, 

 a Handle of the box. 

 h A flip or door which opens inwards by a Joint at c. There is another door like thiy 



on the other fidfi,. 

 c The joint, 

 </ 1 he centre or pin of the joints 



SCIENTIFIC NEWS, AND ACCOUNTS OF BOOKS^ 



AN a Letter from Sig. Fabbroni to Sig. D. Luigl Targioni of Naples, inferted in the- 

 85th No. of the Giornale Letterario di Napoli, I find an account of a very effe£lual com- 

 pofition for extinguilhing fire, invented by M. Von Aken. The compofition is, 



Burnt alunr . _ _ « _ pounds 30 



Green vitriol powdered' - - - 40 



Cinabrefe or red ochre in powder - - - ao 



Potters' clay, or other clay, alfo powdered - - , 200 



Water - - - > _ 630 



With 40 meafures of this mixture an artificial fire was extinguifhed under the direcftion of 



the inventor by three perfons, which would have required the labour of 20 men and 1500 



meafures of common water. Sig. Fabbroni was commiflioned to examine the value of this 



invention, and found in his comparative trials with engines of equar power, worked by 



the fame number of men, that the mixture extinguiflied the materials m cnmbuttion in one- 



fixth part lefs time, and three eighths lefs of fluid than when common water was ufed» 



He obferved, as might indfeed have been imagined fro n the nature of the material, that the 



flame difappeared wherever the mixture fell, and that the faline, metallic and earthy matter*: 



formed an impenetrable lute round the hot combuftible matter, which prevented the accef3> 



of the air, and confequently the renewal of the deffruflive procefs. 



Sig. Fabbroni eftimates the price of this compofition at about one foldo (or halfpenny); 

 per pound, but remarks, that it requires fewer hands, and affords the incalculable advantage 

 of a fpeedier extinftion of the fire. Whence he concludes, that it might be advifeable toi 



keep the ingredients ready powdered to mix with water. 



.9^ Ibavr 



