+---+--------+-----+---------+---------+--------+---------+-------+ | | | |Ht. Water|Ht. Water| Water | |Weight | |Nº.|Heights.| Wt. | before | when | raised.| |Water. | | | | |immersed.|immersed.| |Solidity.| | | |Ft. In. | Pds.| Inches. | Inches. | Inches.| |Pounds.| +---+--------+-----+---------+---------+--------+---------+-------+ | 1| 6 02 | 161 | 19,30 | 21,20 | 1,90 | 2,573 | 160,8 | | 2| 5 10⅜ | 147 | 19,25 | 21,16 | 1,91 | 2,586 | 161,6 | | 3| 5 9½ | 156 | 19,21 | 21,06 | 1,85 | 2,505 | 156,6 | +---+--------+-----+---------+---------+--------+---------+-------+ | 4| 5 6¾ | 140 | 19,17 | 21,21 | 2,04 | 2,763 | 172,6 | | 5| 5 5⅞ | 158 | 19,13 | 21,21 | 2,08 | 2,817 | 176,0 | | 6| 5 5½ | 158 | 19,09 | 21,26 | 2,17 | 2,939 | 183,7 | +---+--------+-----+---------+---------+--------+---------+-------+ | 7| 5 4⅜ | 140 | 19,05 | 21,06 | 2,01 | 2,722 | 170,1 | | 8| 5 3⅛ | 132 | 19,01 | 20,86 | 1,85 | 2,505 | 156,6 | | 9| 5 4⅛ | 121 | 18,97 | 20,76 | 1,79 | 2,424 | 151,5 | | 10| 5 3¼ | 146 | 18,93 | 20,66 | 1,73 | 2,343 | 146,4 | +---+--------+-----+---------+---------+--------+---------+-------+
In making of these experiments, I remarked some inconveniencies, which I did not at first advert to, and which, at that time, I could not prevent. I intended, that each man should have got gently into the water, immersed himself all but his head, and so have staid until the motion of the water had ceased; then he was suddenly to have ducked his head under, and have continued to a few seconds of time, until I had noted the rise of the water; and, after his leaving the cistern, another was not to go in until the water was free from motion. Could these things have been done, as I projected, I could have recommended the foregoing table as sufficiently complete: but I must observe, that beside the men’s being of different sizes from what I had desired, they were in too much haste to be dismissed (with another dram after dressing); so that the water was not quite still when they got into the cistern: neither could I persuade all of them to lay themselves down gently, much less to keep their heads under water so long a time as one second: so that, in most of the observations, the surface of the water was far from being quite so still, as to render the measures perfectly exact, I being obliged to catch them, as it were, by taking the mean height between the librations. Moreover, the great area of the cistern was no inconsiderable bar to the accuracy I expected. However, as I do not recollect experiments of this kind any-where recorded, these, perhaps, may give some satisfaction to such persons, who may have the curiosity to desire some knowlege on this subject. Were I to make any more observations of this kind, I would chuse an upright parallelopiped, not above 18 or 20 inches in the side of the square; into which the person should let himself down by steps nailed to the side: for in so small an area the motion of the water would sooner subside; neither would the librations be any thing near so large as on a smaller surface.