TWEyTY-.SIlTH AXNUAL MEETING. H 



wonderful. Oi'e of the most interesting substances that has been dis- 

 coveied is saccharin. It is made, as are the anilin colors, from coal tar. 

 It is several hundred times as sweet as sugar; so that, if a small particle 

 be placed on the tongue, the impression of sweetness will remain for a long 

 time. If any of you want to go forth as apostles of sweetness and light, 

 you can be fitted out f^-om the chemical laboratory, ana can go forth with a 

 bottle of saccharin in one hand and a coil of magnesium ribbon in the other. 

 You can thus sweeten the walks of men and light their paths in a purely 

 physical sense. 



It is appr(-priate that I should speak of some of the most delicate physical 

 and chemical methods used in making tests. 



One of the most delicate instruments is the spectroscope, the invention of 

 Kirchoff and Bunsen. Without going into details as to the construction of 

 the instrument, it is only necessary to say that by its use it is possible to 

 analyze the light from a heated metal, from the sun, or from the most remote 

 fixed star or comet, and tell of what it is composed. 



One of the commonest substances on the earth is common salt, sodium 

 chloride. We have an immense storehouse of it in the water of the ocean, 

 and it is found deposited in great beds in several favored localities, of which 

 central Kansas i.s one. When sodium, the metal of salt, burns, it imparts to 

 the fiame a yellov/ tint. This can be seen on a large scale if I light a bowl of 

 alcohol that is saturated with salt. You will notice the peculiar cadaverous 

 effect that the light produces on all objects in the vicinity. 



By the use of the spectroscope it is possible to detect an almost infinitely 

 small quantity of this substance. It is estimated that one 195,000,000th of a 

 grain can be detected. A grain is about as much as would lie on the point 

 of a pen-knife. That is considerably less than a "pinch." Lithium, too, 

 has a characteristic fiame reaction. 



The chemist can avail himself also of very delicate tests for ammonia; and 

 he finds these testf5 of the greatest use in the determination of the extremely 

 small quantities of ammonia in air and in water. Yet these tests in water 

 are of great importance to the analyst in helping him to decide as to the 

 purity of a water and whether it is fit for use as a domestic supply. One of 

 these tests is by the use of "Nessler's solution," as it is called. By its use 

 we can detect the one 1,000,000th of a grain, or, to be more practical, we can 

 detect one part of ammonia in 100,000,000 parts of water. 



In an interesting article on "Next to Nothingness in Chemistry," W. H. 

 Pendlebury sneaks of some of the latest discoveries that have been made in 

 the importance of little things. It is wonderful, for instance, what an effect 

 moisture has on the simple process of combtistion. Even the ordinary coal or 

 wood fire does not burn well if the fuel and the air are perfectly dry- It 

 has been shown that if oxygen be perfectly dry, such a combustible sub- 

 stance as phosphorus may be warmed, or even distilled in it, and not take 

 fire. Wanklyn has discovered that dry chlorin will not combine with dry 

 oxygen; but, if the least particle of moisture be admitted, the combination 

 takes place immediately with the evolution of light and heat. 



It has been shown that copper does not act on nitric acid, if both are pure; 

 but the smallest trace of nitrous acid will bring about the combination with 

 avidity. One part of nitrous acid in 10,000 is sufficient. 



What a vast difference the presence of a little impurity can make in com- 

 mercial copper. It will carry twice as many messages used as a telegraph 

 wire if pure as if adulterated with even one-tenth of 1 per cent, of bismuth. 



