2l6 



THE GUIDE TO NATURE 



X> 



What is Dust? 



I was busy at work in the laboratory. 

 Needing something from my bedroom 

 in the residence near by, I went over 

 to get it, and found Airs. Bigelow and 

 the maid "putting tilings to rights," 

 by sweeping and dusting. 



"It is surprising," said Mrs. Bigelow, 

 "how soon these tiny white rolls will 

 accumulate. I wonder where they 

 come from and what they are." 



Here was a suggestion. I gathered 

 a few of the rolls, and took them to 

 the laboratory. Upon examining them 

 under a compound microscope I found 

 that they were composed of compara- 

 tively long and slender white fibers. 

 Very few, if any, dark fibers could be 

 found. It appears that these are cotton 

 fibers and are probably mostly from 

 the sheets of the bed, though I cannot 

 believe they come wholly from them. 

 Some appeared to be from dark colored 

 clothing, but they had become 

 whitened by wear in the same sense 

 that the weather-beaten fibers of a 

 dark fence rail or board becomes 

 whitened as they arp roughed up and 



beaten from the wood. In a few cases 

 I found fibers that were dark in color 

 hut, as is familiar to everyone, the lit- 

 tle rolls of dust that accumulate in the 

 nooks and corners of the room are in- 

 variably white. It makes no difference 

 what are the colors of the clothes 

 within the room, these fibers beaten off 

 from those clothes show the white 

 mark of age so common not only with 

 human beings but with aged fence 

 rails. 



In order to examine these dust fibers 

 under the microscope I had occasion- 

 to take a glass slip that was lying by 

 the miscroscope on a shelf under the- 

 window. 1 started to wipe off that slip 

 with a bit of cloth, after having 

 breathed on it so that the dust fibers- 

 might adhere to the condensed mois- 

 ture. Then it occurred to me that 

 perhaps the dust on that slip might be 

 as interesting as the rolls that had been 

 taken from the bouse. Placing it under 

 the miscroscope, T was surprised to 

 find that with strong reflected light, it 

 had the appearance of a bed of cinders, 

 and such it reallv was, although the 





A PHOTOMICROGRAPH OF A FUZZY ROLL FROM THE FLOOR UNDER A BED. 



