1a PHILOSOPHICAL SOCIETY OF WASHINGTON. 
maps, the substantial results of Lieut. Lockwood’s explorations form 
a tablet more enduring than brass, which the corroding storm, the 
fierce north wind, and the flight of ages cannot efface. 
In reply to a question by Mr. Mussey, Mr. Curtis stated that the 
time for longitude determination was obtained from one ordinary 
watch of good quality, and one pocket chronometer. Messrs. Datu 
and Rosrnson discussed the advantages and disadvantages of the 
use of dogs in arctic sledging, and attention was called to the im- 
portance of using snow shoes, and of coating the sledge runners 
with ice. 
Mr. O. T. Mason made a communication on 
TWO EXAMPLES OF SIMILAR INVENTIONS IN AREAS WIDELY APART. 
[Abstract. ] 
Anthropologists assign similar inventions observed in different 
parts of the world to one of the following causes : 
1. The migration of a certain race or people who made the in- 
vention. Upon this theory similar inventions argue the presence of 
the same people or race. 
2. The migration of ideas—that is, an invention may be made by 
a certain race or people and taught or loaned to peoples far removed 
in time and place. Upon this theory similar inventions argue iden- 
tity of origin, but not necessarily the consanguinity of those who 
practice them. 
3. In human culture, as in nature elsewhere, like causes produce 
like effects. Under the same stress and resources the same inven- 
tions will arise. 
Now, the question arises, which of these causes shall be invoked 
in specific cases to account for resemblances. 
We must first examine the word resemblance. 
Taking Aristotle’s four causes: 
‘The material cause, ex qua aliquid fit. 
The formal cause, per quam. 
The efficient cause, a qua. 
The final cause, propter quam. 
We must enlarge upon them as follows: Every human activity 
involves six fundamental considerations. 
1. The agent, or efficient cause. 
