6gz THE POPULAR SCIENCE MONTHLY. 



work already carefully thought out, which should give the synchro- 

 nous progress of invention, discovery, and learning, from the beginning 

 of recorded history. Many months and a great deal of labor were 

 devoted to research in the various public libraries, and when the under- 

 taking was far advanced toward completion it was forestalled by 

 another work covering substantially the same ground. This was a 

 bitter disappointment, but, wasting no time in regrets, Edward was 

 soon at work on an arithmetic, in which the problems were made up 

 from the constants of science. This enterprise also was anticipated by 

 another book of similar character. But the labor thus bestowed was 

 not wholly lost ; for it helped to educate him in the line of his future 

 work. 



Although occupied most of the time as above stated, my brother 

 kept up the study of agricultural chemistry, and, to this end, ever since 

 my arrival in the city he had been seeking for a laboratory where I 

 could enter as a pupil ; but none was found that would admit a 

 woman, until Dr. Antisell, one of the Irish exiles of 1848, consented to 

 receive me. Here I at once began the studies preliminary to the analy- 

 sis of soils. By the time I was able to make such analyses, my brother 

 had become convinced that they were of no value in practical agricult- 

 ure. But, in our talks over this laboratory experience, he was still hin- 

 dered by the old difficulty of dealing with chemical phenomena at 

 second-hand ; and now an unexpected consequence followed. When 

 he reflected that chemistry was fast becoming a popular branch of 

 education, and that, so far as its processes were concerned, the youths 

 who were studying it might be classed, along with himself, as blind, 

 their situation naturally interested him. Occupied with this subject, 

 there one day arose in his mind a scheme for picturing atoms and their 

 combinations that would bring the eye of the student into more effect- 

 ual service. Out of an impulse to help this unfortunate class came the 

 "Chemical Chart," in which he succeeded in making clear to the eye, 

 and easily remembered, the most important principles and laws of the 

 science as it was then understood. This "Chart" represented the prin- 

 cipal elements, binary compounds, and salts, and the minerals of chief 

 interest to geologists and agriculturists, together with the most impor- 

 tant organic bodies. Atoms of the different elements were shown by 

 diagrams of different colors, the relative sizes of which expressed their 

 combining ratios, and the compounds exhibited the exact numbers of 

 the respective atoms that unite to form them. The chart was at once 

 accepted as a valuable assistance in teaching chemistry by many lead- 

 ing educators throughout the country, and its use led to frequent re- 

 quests that its author would prepare a book to go with it. The text- 

 books consulted in its preparation had left the impression that this 

 science was not so attractively presented to the learner as it might be. 

 lie thought that chemistry could be made enticing as well as intelli- 

 gible to learners who had not the help of experiments in its pursuit. 



