Pendulum Experiments on Mont Cents* 159 



Theschistua . . . 2-81. 

 The marble . . . 2-86. 

 The gypsum . . . 2.32. 



In the absence of a precise knowledge of the quantity and 

 position of each of these three component parts, we may take 

 the mean, 2.66, of their several densities as approximatively 



the density of the mountain, = ^. We have then 

 • ■} nov • 



•rft ^o ^ ^ 5 .02^x39.1154 ^ . „^ 



" 14394 X- 0076 ' * 



a result differing little from that of Cavendish as recently cor- 

 rected by Dr. Hutton, and still less from that of the Schehallien 

 experiments. 



The most hypothetical element of this calculation is the 

 width assigned to the base of the mountain ; but by the very 

 nature of the question, it has but little influence on the final 

 result ; since, by even doubling the assigned diameter, the total 

 attraction would not be altered a twentieth. In regard to the 

 mean density of the mountain, if it were taken at 2.75, instead 

 of 2.66, that of the earth would result 4.94, instead of 4.77, as 

 given above. 



E. S. 



Transactions of the Horticultural Society . Vol. vii. Part 1. 

 4to. London, 1827. pp. 208. 



I. Observations upon the Growth of Early and Late Grapes under 

 Glass. By Mr. James Aeon. 



Few gardens are to be found in which bunches of fresh ripe 

 grapes can be gathered every day in the year : notwith- 

 standing the importance of the fruit to the luxurious, and 

 the facility with which the vine submits to the artificial cli- 

 mate of the forcing-house. Nothing is easier than to secure 

 crops of grapes in a vinery during the spring and summer 

 months ; but it is far more difficult to obtain them in the 

 last and earliest seasons of the year, when the plants would 



