and Laboratory Methods. 1195 



Home Made Wall Charts. 



I can vouch for the value of Professor Heald's method of making wall charts^ 

 described in the November Journal, as many years ago, when connected with 

 the State College of Iowa, I made some very serviceable charts in this way. I 

 soon found that I could use a camel's hair brush for inking the pencil lines. 

 After a little practice one learns just how rapidly the brush must be drawn over 

 the surface to produce the right kind of a line, and to avoid spreading and 

 blotting. I still have a few of these old muslin charts, which are as good as 

 ever, after at least twenty years of service. One great advantage which such 

 charts have over all others is that they may be folded into small, fiat parcels,^ 

 and tucked away in one's traveling bag, and not be any the worse for it, after an 

 extended lecture trip. 



Another method of making charts is one which grew out of the foregoing, 

 and which I prefer for charts for hanging on the walls of the lecture room or 

 laboratory, although less convenient for carrying about the country. I buy a 

 roll of "opaque " curtain cloth, white or of a light shade, and about 100 cm, in 

 width. This is cut into sections of the desired length, say 1}4 to 2 meters, 

 and on these the desired figures are drawn. I buy one pound boxes of paints, 

 ground and mixed, ready for use. In order to hasten the drying of the oily 

 paint, I take out a little from the box, allowing the surplus oil to drain off, and 

 then mix it with the proper amount of spirits of turpentine to make it flow 

 readily from the brush. The figures having been traced in lead pencil, a good 

 camel's hair brush is used in applying the paint. Since the curtain stuff is a 

 kind of " filled " canvas, its surface takes the paint very easily, and there is no 

 danger of its spreading. When the material is white, colored paints may be 

 used to good advantage. I have been able to get good effects from the use of 

 green, yellow, and brown paints of the quality found in the pound boxes men- 

 tioned above. Other colors, especially the reds, and the delicate shades of pink, 

 lavender, gray, etc., are not as satisfactory with these coarser paints as with the 

 " tube " paints, which I have used for finer work, as in cytological charts. For 

 the charts made in black throughout, any good lampblack paint will prove 

 satisfactory. 



In mounting the charts, I have found that the best way is to use pairs of pine 

 or whitewood " half round " strips of the proper length, clapping the end of the 

 chart between the two, and fastening them together with small wire nails. They 

 thus form a cylindrical roller at each end, and the cloth is fastened much more 

 securely than when a solid roller is used. 



I have a hundred or more charts in the Botanical department of the Uni- 

 versity of Nebraska, made in this way, and they have been found very satisfactory, 

 while the cost for material has been little. 

 University of Nebraska. CHARLES E. BeSSEY. 



