I 5 o THE NA TURE-S TUD Y RE VIE W [ s : 6^-sept. , 1 90 » 



around the tumbler about a half inch from the top kept the water 

 from going in. I noticed the water reached to that band. I then 

 took a plain tumbler and they saw that the water entered the 

 tumbler only a short distance, the same as at first. They all 

 admitted then that it was the air that kept the water from filling 

 the tumbler. I then passed the experiment over to my assistant, 

 the teacher of science. He handled the tumbler in every position, 

 but they would not admit that it contained air unless the mouth 

 was held downward. 



He then took a flask partly filled with water, fitted with a cork 

 containing two glass tubes, one ending in the air space, the other 

 below the water surface. By blowing into one tube the water 

 was forced out the other. Several said, "You had water in your 

 mouth." 



He then called a little girl to come up and blow. She did so 

 and the w r ater spouted out. Several others did the same. Then 

 some of the children said, the air in the flask pushed the water out. 

 After they seemed satisfied about this we ended the experiment, 

 but asked some general questions to find out why the tumbler did 

 not hold air when held mouth -up. He asked if we should dig a 

 hole in the ground ten feet deep would the air go into it? They 

 answered, "No." 



How does air get into the cellar? 



"Oh ! Through the side door, or windows, the wind blows it in. " 

 We left them holding the same views. 



I watched the faces of the pupils during the experiment and 

 most of them expressed earnest interest, in fact, more interest 

 than is usually seen in classes of much older pupils. 



We then passed to the fourth-grade class, two years in advance 

 of the latter. We had nearly the same results. None would 

 admit that the tumbler contained air when held with the mouth 

 up. 



Following up the first experiment, it became necessary to pre- 

 pare another experiment to prove that there was air in the tum- 

 bler no matter in what position it was held. To do this, we had a 

 cork which fitted the tumbler. In this cork was placed a glass 

 funnel and a delivery tube. We also had a jar partly filled with 

 water. We then took it before a second-grade class. The opera- 

 tor held the tumbler in various positions and asked them the ques- 



