112 ©. S. Peirce—On a Method of swinging Pendulums. 
the “flow and plunge” structure is the rule. If it can be said 
(as I do not think it can) that no deposits similar to the loess 
are now in process of formation by lakes: neither have we 
at this time, any example of the accumulation of such deposits 
through the agency invoked by Richthofen, on any considera- 
le scale; although the postulated conditions exist in not a 
few regions. All dunes and drifted desert sands show wind- 
formly fine dust into the trough of the Lower Mississippi, 
leaving all the adjoining upland without a vestige for hundr 
of miles on either side: the sum-total of anomalous conditions 
required to sustain the eolian hypothesis partakes strongly of 
the marvellous. 
Art. X VITI.— On a method of swinging Pendulums for the deter- 
mination of Gravity, proposed by M. Faye; by ©. S. PEIRCE. 
[Read before the National Academy Academy of Sciences, April 17th, 1879, with 
authority of the Superintendent of the U. 8. Coast and Geodetic Surve: 
At the Stuttgart, 1878, meeting of the International Geodetic 
Association, M. Faye suggested a method of avoiding the 
flexure of a pendulum-support which promises important ad- 
vantages. The proposal was that two similar pendulums should 
be oscillated on the same support with equal amplitudes and 
ene phases. If the pendulums oan be made precisely 
ke, the amplitudes precisely equal, and the phases precisely 
opposite, it is obvious that the support would be continually 
solicited by two equal and opposite forces and would undergo 
no horizontal flexure, except from the distortion of the parts 
between the two edges. But since none of these three elements 
can be made equal, it is necessary to inquire what would be 
the effect of such slight imperfections in their equalization a5 
would have to be expected in practice. 
