Mat 19, 1911] 



SCIENCE 



779 



■with consequent disheartenment and lack of 

 interest in the work. 



In considering Group I., consisting of lead, 

 silver and mercury, the student is given a 

 typewritten sheet of reactions to perform. 

 These are carefully selected to bring out the 

 properties of the elements, especially those 

 which are of most importance in qualitative 

 and quantitative analysis. At the completion 

 of the experiments on silver or on silver and 

 lead, in place of throwing out the contents of 

 his test-tubes, the student takes them to the 

 instructor in charge, and the latter, a man of 

 experience, after examining the work care- 

 fully, gives him a thorough quiz on it. If 

 this work, as well as the student's knowl- 

 edge of the reactions, etc., is satisfactory, the 

 instructor places his O. K. upon the sheet. If 

 neither the quiz has been passed in a credit- 

 able manner nor the student been able to ob- 

 tain the correct reactions, the contents of the 

 test-tubes are thrown out and the work re- 

 peated. After a second trial, if the experi- 

 ment is still unsuccessful, the instructor 

 should demonstrate it. By this means the 

 student is taught independence, there is cre- 

 ated in him ability to do things for himself; 

 the instructor is enabled to " keep tab " on 

 the work accomplished, knows if the student 

 has obtained the correct result and yet does 

 not allow him to spend an undue amount of 

 time on something which it is clear he does 

 not understand. 



This quiz demonstration system is varied to 

 suit the needs of the individual. These, the 

 instructor, coming in personal contact with 

 each student as he does, soon comes to know. 



Before the younger men of the force are al- 

 lowed to quiz, they should observe the meth- 

 ods of the instructor in charge and then be 

 subject to his direct supervision from time to 

 time, when they themselves are quizzing. 

 Thus, in as far as is possible, the policy of the 

 laboratory is uniform and at the same time 

 consistent with the individuality of the per- 

 sons in question. 



Upon completion of the preliminary work 

 upon a particular group, the separation of the 

 included elements is studied in a similar man- 



ner. When the results of this work have re- 

 ceived the O. K. of the instructor the student 

 is given a number of simple unknowns on this 

 group. I find that by requiring that he do two 

 of these for every one upon which he makes a 

 mistake, his mistakes become fewer in number 

 and his confidence in his ability thereby in- 

 creases. In taking up the second and follow- 

 ing groups, the separations and preliminary 

 work are treated similarly to group one, ex- 

 cept that when time is available one of the 

 unknowns is made to contain one or more of 

 the elements of the preceding group. In this 

 way the separation of the various groups may 

 be quizzed over as in the separation of each 

 group. 



The groups and acids take up somewhat 

 over one half the time allotted to the course. 

 Then come the general unknowns, where the 

 work of the student is expected to be carried 

 on independently. Several simple mixtures 

 are first given, that the student may better 

 connect the group separations. In these both 

 the metal and acid are identified. Then fol- 

 low a number of commercial products, con- 

 sisting of minerals, slags, alloys, etc., the se- 

 lection being governed, to a certain extent, by 

 the particular field which the student is likely 

 to enter. In this district mining interests are 

 of most importance, hence, ores, minerals, 

 slags, etc., make up this portion of the course. 



Individual quizzing on this part of the work 

 is not as frequent as before, but when report- 

 ing an unknown, the student is quizzed on re- 

 actions, method of separation, identification, 

 etc. Here class-room quizzing is of more 

 value and can be advantageously used to 

 supplement part of the work with the individ- 

 ual, for, provided he be properly trained in the 

 power of observation, a great amount of 

 knowledge can be gleaned by the student from 

 the mistakes of others, brought to his notice 

 by this group questioning. 



At this point too much stress can not be laid 

 upon the exceptions to the general rules and 

 the reason for each step taken in the separa- 

 tion. Herein is differentiated the training of 

 the professional from the routine chemist. I 

 find, also, at this point in the training, of the 



