Chemistry and Physics. . 467 
saa 076, y = °029 + *065 
These ies ihedlly seem to present evidence of a tidal yield- 
ing of the earth’s mass, and the value of the 2 is such as to show 
a pee sbsctive rigidity of the whole earth is about equal to 
at o 
Bat this area is open to some doubt for the following reason : 
Taking only the Indian results (forty-eight years in all), which 
are much more consistent than the English ones, I find 
a = ‘931 4. 056, y = 155 + 068 
We thus see that the more sae whe observations seem to 
bring out the tides niore nearly to r theoretical equilibrium 
values with no elastic yielding of the soli d. 
It is to be observed, power that the Indian results being con- 
fined within a narrow range of latitude give (especially when we 
consider the absence of anrtiite accuracy in my evaluation of the 
definite integral) a less searching ares for the elastic yielding than 
a oe of results from all latitudes 
On th ole we may fairly Sonciias that, while there is some 
evidence of a tidal yielding of the earth’s mass, that yielding is 
certainly small, and that the effeetive rigidity | is at least as great 
as cy of steel. 
2, ipple-marks.—Two memoirs on the formation of ripple- 
marks Nave recently appeared ; one, by Mr. A. Hu 
Transactions of the Royal Society for 1882, and the other 
Mr. C. DeC i i 
“ 
sei matter in contact with a Rewid of less vis- 
cosity undergoes oscillatory or intermittent friction resulting from 
movement in the overlying layer, or from its own displacement 
relatively to this layer, (1) the surface of the viscous matter be- 
comes rippled perpendicularly to the direction of the pape 
and (2) the distance between the — so formed is in direc 
ratio to the amplitude o iad oscillat 
T atter oe ‘includes not ag eR 
s 
feeble Sania of ae paficient ¢ 0 give seg ge to 
