Ij6 Experiments to afcertain 



(§. 30.) Refults of the Obfervations of the Sphere collected.. 

 Correft weight of a bulk of water = fphere, the barometer -At a depth below 



being at 29,74 inches, thermometer 66°,o. "^^ '^"''f''" °f/^^e 



grains. inches. 



5,6 



By the ift obfervation - - - . _ 28672,79 



2d obfervation _ _ - - 28673,06 



3d obfervation _ _ . - 28674,6: 



3'7 

 6,8 



5>37 



Mean of all - - - - - 28673,5: 



Which, I think, may fairly be prefumed to be within 1 part in 50,000 of the truth. 

 (§• 3'-) Now the contents of this fphere having already (§. 28.) been found to be 



= ii^.ciQ cubic inches; = 252,587 grains, will be the weight of a cubic inch 



^^ ^ ii3'5i9 ' °- , . . . ° 



of diftilled water, under the circumftances above mentioned^ by Mr. Troughton's weights *, 



I think it may now be concluded, that the variety in the experiments of the cylinder and 

 the" cube, (§. 24.) does not proceed from the different depths f in the water, at which thejf 

 were made ; at leaft, that the preffure of 3 inches, in perpendicular height of water, does not 

 render that fluid more denfe by joioo part, which rnaj be reckoned an infenfibie quantity j 

 but that this variety did proceed from a difference in the yielding of the fides of the cube and 

 the cylinder. And laftly, I hope it may be truftcd, that the weight of a buHe- of water := the 

 fphere, has been determined to within 30^00 of the. whole, and probably to within half that 

 quantity. 



(§. 32.) Having then, through the means of Mr. Whitehurft's obfervations, and of his 

 own inftrument, afcertained the length of his propofed ftandard, in the' latitude of London, 

 113 feet above the level of the fea J, under a dcnfity of the atmofphcre correfponding to 3a 



* But, as will appear hereafter (§. 41.), thefe weights afe too lighf, when compared with the ftandard in 

 the houfe of commons, by about i in 1523,92; the corrcftion, therefore, for this difference, would be 

 = 0,165 grain, to be dedufted from - r - - 252,587 grainsv 



— .165 



Anil the weight of a cubic inch of diftilled water, in grains of the parliamentary ftandard, ) _ 



will be - - - - - - - i -2.^.4" 



•|- By means of an alteration and addition to my apparatus, fince the experiment above mentioned was made, 

 I have been able to repeat it at greater depths below the furface of the water, viz. when the centre of the 

 fphere was 5 inches, 13 inche?, and 21 inches, below, without any appearance of water having a fenfible dif- 

 ference of denfity at different depths. The veffel 1 ufed for this purpofe was of wood, 32 inches high, and 

 12 fquare, containing 16 gallons, with two fides of plate-glafs, to admit the light ; and the wires by which 

 the fphere were fofpended were 45 inches long, and ftronger than before, viz. lOo inches of the fingle wire 

 weighed 24,14 grains ; and due allowance was made for the different weight of the fcale and wires, in air and 

 water, from aftual experiment. 



J The height, as I have been informed, of the room of Mr. Whitehurft's obfervations. 



inches 



