MEAN DENSITY OP THE EARTH. 
371 
It should be stated that the result of the work on Maui is 
due entirely to the liberality of the Hawaiian government. 
The triangulation had been completed before my visit and 
the gravity and latitude observations were made with the 
aid of the government survey staff, Professor IV. D. Alex¬ 
ander, the surveyor general, being present much of the time. 
On Hawaii the expenses were principally borne by the Ha¬ 
waiian survey and I again had the efficient services of several 
of the officers connected therewith. Mr. F. S. Dodge and 
Mr. W. A. Wall both took part in the gravity determinations 
on Haleakala. On Mauna Kea, besides Professor Alexander? 
the survey corps was represented by Messrs. W. E. Wall, 
E. D. Baldwin, and W. Chamberlain. Mr. J. M. Muir ac¬ 
companied the party as voluntary observer. The steward 
was Mr. Louis Koch, and Kauwe, an experienced Kanaka 
guide, led the expedition from Kalaieha to the summit at 
Waiau. 
Assuming that the law of attraction is that of the inverse 
square of the distance, the measure of the force/, exerted by 
any mass, M, at a distance, d, from the attracted point, may 
be written 
> M 
f== d 
a) 
the unit of force being that force which acting during a unit 
of time will impart to a unit of mass a unit of acceleration. 
The above formula is to be interpreted in such units; other¬ 
wise it is necessary to introduce a constant factor, k, which 
will then represent in C. G. S. units the force which will give 
one centimeter of acceleration to a mass of one gram in one 
second. Then the actual force/, in dynes, will be given by 
the formula 
<*> 
when the symbols M and d are expressed in grams and centi¬ 
meters. The value of h is 0.000 000 067 or 67 -5-10 9 . The 
attraction of any irregular mass may be had by finding an 
