94 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



5. In reference to the assumption that primary waves do 

 exist in the South Pacific Ocean, the annual record gives a 

 brilliant confirmation of that which the earthquake Avaves 

 had first revealed, viz., that the assumption is thoroughly 

 erroneous. 



6. The level of the sea at Sydney stood at the end of the 

 year 1871 one foot six and a half inches higher than at the 

 beginning of the year, and had been gradually increasing 

 during the year to this maximum, with, however, various ir- 

 resfular sinkinscs in the mean time. 



The removal of the water of the ocean from the northern 

 hemisphere to the southern, which is thus demonstrated, is 

 looked upon as a remarkable confirmation of the views of the 

 author, at least in kind if not in degree; and he adduces a 

 calculation showing that the moon, in a period of four years 

 and five months, can draw a stratum of water five inches 

 deep to the northward, and a stratum somewhat deeper than 

 this to the southward. These relations will be reversed at 

 some future time, Avhen the perigee of the moon has a difter- 

 ent relation than it at present has to the earth's orbit. A 

 further demonstration of the truthfulness of Hochstetter and 

 Schmick's theory of the periodical variation of the level of 

 the ocean is drawn from the observations made in the North 

 Sea during the past sixty years. It is ordinarily assumed 

 that these observations, which have been already examined 

 by many authors, especially Berghaus and Moberg, show a 

 steady diminution of two feet in a century, and, assuming the 

 variation to be uniform, it would amount to 210 feet in 10,500 

 years. Of this change one third is attributed by Schmick to 

 the influence of the sun, and the remaining two thirds to that 

 of the moon. In the work before us we do not s^e any ref- 

 erence by the authors to the known change in the relative 

 position of the land and Avater caused by the secular cooling 

 of the earth, the eflfect of which, as recently developed by 

 Mallet, seems to us sufficiently to account for the change ob- 

 served at Sydney, Australia. There seems but slight reason 

 to attribute it, we think, to a periodic variation in the height 

 of the water of the Southern Pacific Ocean, depending on the 

 position of the moon's perigee and the earth's perihelion. 7 

 C, 1873, 375. 



