1853.] Experimental Investigation of Table-Moving. 387 



upon the upper card, and we waited for the result. Now, the 

 cement was strong enough to offer considerable resistance to 

 mechanical motion, and also to retain the cards in any new 

 position which they might acquire, and yet weak enough to 

 give way slowly to a continued force. When at last the tables, 

 cards, and hands all moved to the left together, and so a true 

 result was obtained, I took up the pack. On examination it 

 was easy to see by the displacement of the parts of the line, 

 that the hand had moved further than the table, and that the 

 latter had lagged behind ; that the hand, in fact, had pushed 

 the upper card to the left, and that the under cards and the 

 table had followed and been dragged by it. In other similar 

 cases when the table had not moved, still the upper card was 

 found to have moved, showing that the hand had carried it in 

 the expected direction. It was evident, therefore, that the 

 table had not drawn the hand and person round, nor had it 

 moved simultaneously with the hand. The hand had left all 

 things under it behind, and the table evidently tended con- 

 tinually to keep the hand back. 



The next step was to arrange an index which should show 

 whether the table moved first, or the hand moved before the 

 table, or both moved or remained at rest together. At first 

 this was done by placing an upright pin fixed on a leaden foot 

 upon the table, and using that as the fulcrum of a light lever* 

 The latter was made of a slip of foolscap paper, and the short 

 arm, about ^ of an inch in length, was attached to a pin 

 proceeding from the edge of a slipping card placed on the 

 table, and prepared to receive the hands of the table-turner. 

 The other arm, of ll| inches long, served for the index of 

 motion. A coin laid on the table marked the normal position 

 of the card and index. At first the slipping card was attached 

 to the table by the soft cement, and the index was either 

 screened from the turner, or the latter looked away : then, 

 before the table moved, the index showed that the hand was 

 giving a resultant pressure in the expected direction. The 

 effect was never carried far enough to move the table, for the 

 motion of the index corrected the judgment of the experi- 

 menter, who became aware that, inadvertently, a side force 

 had been exerted. The card was now set free from the table, 

 i. e. the cement was removed. This, of course, could not 



