340 POPULAR LECTURES AND ADDRESSES. 



weighted by a piece of lead attached to one end, so 

 that each mass wood and lead just floated on 

 water. On the 4th February, icS.S/, these three 

 cylinders were placed on the surface of the shoe- 

 maker's wax, one with the weighted end down, 

 another with the weighted end up, and the third on 

 its side ; and there you see what has been going on 

 during the year. The first cylinder has sunk 

 steadily into the wax ; the second has toppled over 

 and is sinking to a vertical position with the 

 weighted end down ; the third has attained a 

 vertical position and is nearly as deep in the wax 

 as the first. 



I would call your attention to another illustration 

 of the viscosity of this seeming solid. There is a 

 piece of shoemaker's wax which was levelled down 

 with heat and then allowed to become cold. Two 

 months ago, on the i6th December, 1887, we placed 

 on its surface the 16 pieces of wood cylinders'and 

 cones which you sec are very slowly sinking into 

 the wax. Here again I have pieces of wood shaped, 

 and some of them with lead attached, exactly 

 as arc those on the wax. See the positions they 



