176 



main a matter ot chance and the experin:ent. seemingly so simple but 

 m reahty so complicated, can not well be put into the hands of students 

 doing then- tirst work in chemistry. 



Modiflcations of the experiment which will avoid these sources of 

 error are in the mind of the writer, but have not been subjected to test 

 for lack of time. Should they prove successful I shall be pleased at some 

 future time to communicate them to the Academy. 



An Apparatus for Illustrating Gharles\s and 

 Boyle's Laws. 



James H. RAxsoii. 

 Some difficulty having been experienced in making clear to students 

 the changes in the volumes of gases due to the simultaneous changes in 



temperature and pressure, it seemed that a clearer notion could be given 

 by having a single piece of apparatus to illustrate their laws. Such an 



