APPENDIX 



451 



SYNOPSIS OF COURSE IN INTRODUCTORY CHEMICAL MICROSCOPY. 

 CORNELL UNIVERSITY DEPARTMENT OF CHEMISTRY. 



I. MICROMETRY. (See pages 180-190.) 



i. Determine the ocular micrometer scale values for each of the three objectives 

 attached to the nose-piece of the microscope. Fill out in your note book the data 

 called for in the following table. 



MICROSCOPE No. . . 



2. Thickness of Paint Films. (See page 196.) Count the number of coats of 

 paint on the wooden block given you. Record their colors in the order in which 

 they occur, numbering from inside out. Are they all of the same thickness? 

 What are the variations in thickness if any? Do the paint films differ in character, 

 in uniformity of spreading? Assuming that there has been no shrinkage, how 

 many square feet of surface will be covered by i gallon of paint number 2 (counting 

 from the wood outwards) if applied to the same kind of surface? Record in your 

 note book the serial number of the sample and all data. 



3. Estimation of Weight. (See page 209.) Measure at least three different 

 diameters of the metal bead found in the preparation given you. Average the 

 results and compute the weight of the bead. 



4. Calibration of Sieves. (See page 194.) Determine the number of meshes to 

 the inch; the average diameter of the wires; the average diameter of the openings. 

 Ascertain whether the meshes are uniform or variable. Calculate the diameter 

 of opening and the number of meshes to the inch of the next finer sieve the diameter 

 of whose openings would have to that measured a ratio equal to the square 

 root of 2. 



5. Does a given powdered material conform to specifications? Consult the specifi- 

 cations posted on the bulletin board. Spread the material in question evenly on 

 an object slide. Adjust the drawing camera (see pages 128 and 129). Draw the 

 outline of the grains clearly and sharply upon a note book page. Use great care 

 to sketch the particles in average areas. Remove the preparation and without 

 making any other changes, slide a stage micrometer in place. Trace at the lower 

 right-hand corner of the page five or more divisions of the stage micrometer. By 

 means of the scale thus drawn measure the particles as sketched and ascertain 



