LABORATORY MANIPULATION 



paper in the funnel. Do not fill the filter too full. An 

 eighth of an inch or so should always be left between the 

 surface of the liquid and the edge ^ 

 of the paper. The stem of the 

 funnel should always be left against 

 the side of the beaker or cylinder so 

 as to avoid spattering. The ma- 

 terial left on the filter-paper is 

 called the precipitate or residue. 



31. Laboratory Note-book. 

 Each student should keep a careful 

 record of his laboratory work. The 

 note-book should be complete and 

 should represent the student's in- 

 dividual work. With each experi- 

 ment a number of questions are 

 asked, and the record of the experi- 

 ment should embody the answers 

 to these questions. Do not make 

 short answers, as "yes" and "no," 

 but make a complete statement, 

 giving an intelligent answer to the 

 question. Do not copy the laboratory directions into 

 your note-book, but state briefly and concisely, (i) what 

 the experiment is about, (2) the materials used, (3) the 

 apparatus employed, (4) what you have observed in ma- 

 king the experiment, (5) the chemical and other changes 

 that have taken place, and finally what the experiment 

 proves. In writing up the note-book, it is not necessary 

 to separate the topics, but all the questions should be 



Fig. 12. Filtering. 



