I02 Bird -Lore 



departure were incomplete. Before entering upon the theory it 

 might be as well to inquire a little into the practical working of 

 orientation. The act of orientation is extremely difficult to observe. 

 When an animal goes astray we know generally where he has been 

 lost ; but we do not know, very often, by what way he has reached 

 that particular place. If we let loose a flock of Carrier Doves we soon 

 lose sight of them, and we only find them again in the Dove cote. 



Between the point of departure and the point of arrival there is 

 a lacune for the observer. It is this gap we think we have suc- 

 ceeded in filling. 



Basing ourselves on laws purely hypothetical at the beginning, 

 we have succeeded in reconstituting the complete itinerary of animals 

 closely observed, to follow them, in a way, step by step. We have 

 equally studied the fault of instinct, the error of orientation, and we 

 have verified that the puzzled animal obeys the rules, confirming the 

 laws which we are going to formulate. 



We had at our disposal a grand field for observation. M. le 

 Ministre de la Guerre gave us the task of constructing a movable 

 Pigeon cote, which represents the practical illustration of our theor}'. 

 Finally, La Compagnie Transatlantique requested us to organize a 

 Carrier Pigeon post to be utilized for the service of their steamships. 

 To the numerous experiences on land and sea we have added very 

 interesting observations, of which the results have been communicated 

 to us by credible witnesses. 



To sum up, we bring a great number of facts, man_v of which, 

 controlled by the ofBcial reports of the commissioners representing 

 the Minister of War, have the character of veritable discoveries. 



We have grouped the acts of orientation in two categories : near 

 orientation, attributed to the exercise of the five senses, showing 

 observation at work and, in a certain sense, reasoning and intelli- 

 gence ; and distant orientation, an act purely mechanical, accomplished 

 by means of a subjective sense to which we give the name of the 

 Sense of Direction. 



In each of these two cases the mechanism of orientation obeys 

 distinct laws. 



In the study of mathematics we often employ a method which 

 consists in considering as proved a proposition presented as a 

 problem and in drawing a deduction from it. 



We will do the same. Let us admit as a hypothetical law that 

 the instinct of orientation is a faculty tliat all animals possess in a 

 greater or less degree, of resuming tlie reverse scent of a road once 

 crossed by them, and then let us use it to explain certain facts not 

 explicable in any other way. 



