ACADEMY OF SCONCES] BIOGRAPHY 5 



Of his vocations as a chemist, as a teacher, and as an investigator, others, who knew him 

 more intimately, are better qualified to speak. My impressions of him were formed, unfortu- 

 nately for me, during the last 15 years of his life and then only in the capacity of a distant 

 administrator. What impressed me most from the inception of acquaintance with him was 

 his tenacity of purpose. He had a problem to solve and he was willing to go to any extent of 

 time and effort to reach an effective solution. This attitude, it may be remarked, affords one 

 of the surest tests of the productive investigator. He who wanders, or vacillates, or lacks 

 capacity to concentrate attention on a limited range of phenomena, is almost certain to become 

 lost in a maze of futilities. The impression gained of him as a teacher was that he would probably 

 "neglect" his students. But if this was the case, it must have been, as with Rowland and with 

 Mall, a great privilege for the students. To be permitted to "stand around" in the presence of 

 evolving knowledge is the highest opportunity a university can offer and the greatest favor a 

 worthy student may seek. The best teachers are not those who think most for their students, 

 but those who make the students do their own thinking. In the higher work of a university, 

 at any rate, it is essential that the novitiates learn early to use their own heads. 



The special work of Morse with which it was my good fortune to become somewhat 

 acquainted was his research on the osmotic pressure, carried on by aid of grants made to him 

 by the Carnegie Institution of Washington. What is called osmose, or osmosis, is a subject 

 beset by technicalities, but its elementary essentials are easily apprehended. When two liquids 

 or gases are separated by a common membrane, there is manifested a tendency to transference 

 from one side to the other through the membrane; and if the liquid or gas to which the transfer 

 takes place is confined, an increase of pressure will result, and this under some circumstances 

 may be not merely appreciable but very great. A homely illustration of osmose and osmotic 

 pressure is afforded in the preparation of cranberry sauce. If osmose is permitted to act, the 

 result will be a good sauce; if osmose is prevented the result will be a bad sauce. Osmose 

 follows slowly if the berries are immersed in a hot solution of sugar; meantime the skins will 

 partake of the general dissolution and become edible with the rest of the gelatinous mass. 

 On the other hand, if the berries are boiled and stirred violently, the well-known inedible product 

 follows. 



Briefly stated, the research to which Morse made a capital contribution in this field was 

 that of determining what, for a given membrane and for a determinate range of solutions 

 and of attending temperatures, are the pressures generated. To this research he brought 

 a degree of patience, persistence, and continuity worthy of the highest praise, and by its prose- 

 cution to definite conclusions he won for himself a place among the masters in experimental 

 physics. Just as we look with admiration, for example, on the early work in optics of the 

 Arabian physicist and mathematician, Alhazen, so the world will regard with admiration the 

 man who first measured with precision the far more difficult data leading to definite knowledge 

 of osmotic pressures. 



All researches best worth while in physical science are beset by obstacles which try the 

 souls of investigators. Most of their time and effort are required, usually, in surmounting 

 these obstacles. This was the case with Morse. He needed a uniform, stable membrane, 

 capable of withstanding repeated pressures of many atmospheres. He was led to use a porous, 

 earthenware cup as a matrix for.the electrolytic deposition of metallic salts which furnished the 

 required uniformity of porosity. But it turned out that the potters could not make a cup of 

 sufficiently uniform texture and of sufficient strength to stand the pressures developed. Hence 

 Morse had to apply his science to the art of pottery and learn how to select, to sift, to compress, 

 and to burn clay. This was a task that consumed the greater part of his time for about a 

 decade. But while this was the greatest of his difficulties, it was only one of them. This 

 may suffice here, however, to indicate that the tenacity of purpose already referred to was an 

 indispensable requirement to the success of his project. Baffling and discouraging as was his 

 early experience in this work, Morse never rested until he completed a well-rounded and definite 

 chapter which must be considered the first great classic on the experimental side in the field 

 of osmotics. 



