39^ Mr. Nicholfons Defcription cf, i^c. 



of. They who are inclined to be contented 

 with a lefs degree of precifion than is intended 

 in the conftrudion here defcribed, may change 

 the ftem, which for that purpofe may be made 

 to take out, for a larger. 



One of the greateft difficulties that attends 

 hydroftatical experiments, arifcs from the attrac- 

 tion or repulfion that obtains at the furface of 

 the water. After trying many expedients to 

 obviate the irregularities arifing from this caufe, 

 I find reafon to prefer the fimple one, of care- 

 fully wiping the whole inflrument, and efpecially 

 the ftem, with a clean cloch. The weights in 

 the difh mufl: not be eftcemed accurate, while 

 there is either a cumulus, or a cavity, in the 

 water round the ftem. 



I am, Dear Sir, 



Your affedionate humble Servant, 

 WILLIAM NICHOLSON. 



London, "jfune i, 1784.. 



MEM0in,3 



