GE>fERAL CHARACTERISTICS. 13 



with him. This instrument, the most powerful by far that we 

 ever had seen, gave us a practical peep into the domain of the 

 infinitesimal. 



38. Better than any other description of the smallness of 

 atoms is that given by Flammarion, in. his "Astronomie Popu- 

 laire" : 



"It is proven," he says, "that an atom cannot be larger 

 than one ten-millionth of a millimeter. It results from this, 

 that the number of atoms contained in the head of a pin, of an. 

 ordinary diameter, would not be less than 



8,000,000,000,000,000,000,000. 



And if it was possible to count these atoms, and to separate 

 them, at the rate of one billion per second, it would take 2-50,- 

 000 years to number them." 



29. Girard reports, as follows, an experiment on the olfac- 

 toi-y organs of our little insects: 



"While a bee was intently occupied sucking honey, we 

 brought near her head a pin dipped in ether. She at once 

 showed symptoms of a great anxiety; but an inodorous pin re- 

 mained entirely unnqticeel. ' ' 



30. Whatever be the location of their olfactory organs,. 

 they are unquestionably endowed with a maivelous power of 

 detecting the odor of honey in flowers or elsewhere. 



One day we discovered that some bees had entered our honey- 

 room, through the key-hole. "We turned them out, and stopped 

 it up. Some time after, more bees had entered, and we vainly 

 searched for the ere^•ice that admitted them. Finally a feeb'.e 

 hum caused us to ncjtice that they were coming down the 

 chimney to the flre-place, which was closed by a screen. The 

 wedge which held this screen having become somewhat loose, 

 the motion of the screen in windy weather opened a hole just 

 large enough for a bee to crawl through. A few bees were 

 waiting behind the screen, and as soon as its motion allowed 

 one to pass, she manifested her joy by the humming which 

 led to the discovery. These bees, escaping with a load, when. 



