826 THE POPULAR SCIENCE MONTHLY. 



lusks. The Peruvians and the Mexicans knew how to place the 

 colors upon their cloths. The goods were then exposed to the action 

 of the light, and tints varying from a delicate rose-color to a dark 

 violet were obtained. The colors were so well fixed that they were 

 not even modified by the decomposition of dead bodies. In the col- 

 lection of cloths from the Peruvian huacas at the museum of the Tro- 

 cadero, in Paris, wrappings of mummies that have been buried for 

 centuries still retain the primitive color on their time-eaten threads. 



The Mexicans probably obtained the remarkably brilliant coloring 

 of their pictographs by somewhat analogous processes. These picto- 

 graphs, manuscripts of which only a smaller number have reached us, 

 embrace the history of the country, its national traditions, the geneal- 

 ogies of its kings and nobles, the rolls of provincial tributes, the laws, 

 the calendar, religious festivals, and the education of the children a 

 complete summary, in fact, of all that concerns the manners, customs, 

 and life of the people. They were painted in various colors on cotton 

 cloth, on prepared skins, or on a strong and tough paper made from 

 the fibers of the agave. At times the artist depicts scenes from real 

 life ; at other times he records facts by means of hieroglyphical, 

 symbolical, or phonetic characters, conventional signs that have been 

 handed down for generations, and on which innovation is prohibited. 

 Another series of pictures illustrates the education of children and 

 their food and punishments. The father teaches his son to carry bur- 

 dens, to steer a canoe, or to manage the fishing-tackle. The mother 

 instructs her daughter in domestic duties ; she sweeps the house, pre- 

 pares tortillas, and weaves cloths. These pictures present the distinct 

 outlines and bright colors which the Americans sought first of every- 

 thing. Evidently we must not ask them for models of decorative 

 painting. Their complete ignorance of proportions and the laws of 

 perspective demonstrates that their art was the exclusive product of 

 their own genius, or of the instinct of their race, and that they had 

 not been subject to any foreign influence. Translated for the Popular 

 Science Monthly from the Revue des Deux Mondes. 



-+*+- 



RECENT GEOLOGICAL CHANGES IN WESTERN 



MICHIGAN. 



By C. W. WOOLDE1DGE, B. S., M. D. 



WESTERN Michigan is a region noted for its lumber, its peaches, 

 and its sand. It has other claims, however, to the attention 

 of those who are interested in the workings of Nature, that are not 

 nearly so well known as they deserve to be, for it bears the marks 

 of very extensive geological changes in recent times, which are even 

 yet in progress, but have not attracted the attention that their im- 



