Some Natural Substances which the Chemist Makes.

Te Aroha News, Volume VII, Issue 472, 17 May 1890, Page 6

Some Natural Substances which the Chemist Makes.

By Professor Ira Remsen, Acting President of John Hopkins Uni" versity. [Copyrighted 1890 by S. S. McClure]. What is a chemist ? If I should ask a number of my young friends this question they would not all give the same answer ; and f indeed, it is hard to give one answer which lg satisfactory. Most of you would probably say ‘ a chemist is one who finds out what things are made of.’ Others, perhaps, would say ‘ a chemist is one who can tell whether there is poison in a thing.’ Both answers would be right, but neither tells enough. If you were to ask me, 1 should say that a chemist is one who is trying to find out all he possibly can in regard to the composition of everything he can get hold of, and to learn how these things act upon one another. Hundreds of years ago there were men, called alchemists, who were trying to find something with which they could make gold out of other metals. They thought that, if they could only find the right thing, they would be able with its aid to change lead and iron and other ordinary metals into the valuable metal, gold. They wanted to get rich, just as people nowadays do. They did not find what they were looking for, but they did find a good many things they were not looking for, and the world was richer for what they learned. After a time, chemists began to examine the plants in the hope of finding substances with which to cure their diseases. In this way a large number of interesting and valuable things were discovered. Only a few of these proved to be of value as medicines. Some were useful as dyes, and some as flavours ; but most of them had no practical value. As years passed on, more and more was learned in regard to these susbtances which are formed in nature. Chemists examined them in their workshops or laboratories. They learned how to get them easily from the plants. They learned what they are made of, and they showed the world how to use many of them. And then at last they found that it is not necessary to go to the plants for some of these substances, but that they can be made in the laboratory without the aid of the growing plant. At first many good people thought there was something wrong about this ; they thought the chemist was doing something he ought not to do. Others said that these things which the chemist is making in the laboratory are not the same as those which are formed in the beautiful plants. Life is mysterious, wonderfully mysterious, and it is not possible that the chemist can make the same substances in his glass vessels, his retorts, and flasks, and test tubes that are made in the plants which grow so silently and steadily in the air and sunlight. But all these good people were wrong. The chemist was not doing anything he ought not to do. He was not making life less of a mystery, but was helping to show us all how great a mystery it is. The things he

made were in many cases, at least,shown to be exactly the same as those found in nature, and it is of some of those things I want to tell you. You have probably all heard that there is a substance called coal tar. It is formed when coal is heated for the purpose of making the gas which we use to give us light. When the coal is heated a great many things are formed. Some of these are liquids, some are gases, and some solids. The gases are passed through tubes which are kept cool, and the liquids and solids then collected in other tubes. This mix-

ture is called coal tar. It is a disagreeable, thick, black mass. When coal gas was first made, this tar was thrown away, but r it came to be hard to get rid of it, and, after a time, chemists began bo examine it ( to find out what was in it. And they found that by passing ste im through it, beautiful, colourless liquids could be got from it: and these turned out to be substances of great interest. They are now made from coal tar in enormous quantities and many of the dyes in common use are made from them. Jt is sometimes said that these dyes are got out of coal tar. This is not true ; but it is true that they are made from substances which are got out of the tar. One of the substances thus made from coal tar is the dye commonly called turkey red, but more correctly known as alizarin. This was first obtained from madder, the root of a plant which grows in some parts of France and Italy. Chemists analysed the beautiful red substance and found that it contained carbon and hydrogen and oxygen. Then they found that they could get from it a substance which is in coal tar; and then that by taking this substance and making use of several processes which cannot be described in a simple way they would make alizarin trom it. This alizarin which they made in the laboratory is the same as that obtained from madder. At the present time nearly all the turkey red used is made in factories, and the plant from which it was formerly obtained is not cultivated. In a recent year 14,000 tons of the dye were manufactured, and this had a value of about $8,000,000. Indigo is obtained from plants which grow in India, China, and a few other countries. It is a very valuable blue dye, and is used in large quantity. Every year over 8,000 tons are produced, and this has a value of about $20,000,000. Chemists have long been trying to find out exactly what it is, and they have succeeded in finding out a great deal about it. As a result of the work which has been going on for many vears, it is now possible to start with some of the substances contained in coal tar, and from them build up in the laboratory and in the chemical factory the same blue substance which is obtained from the indigo plant. But it costs more to make it artificially than it does to get it from the plants, and the plant is, of course, still cuitivated. In time the factory will do the work of the plant, as in the case of turkey red. I have given you two examples of substances with colour made from coal tar ; let me now tall you of a few substances with taste, made from the same source. The first of these is the oil of bitter almonds. The name shows how it is formed in nature. It is valued for its taste and odour. There is no difficulty in making it from coal tar, and it is thus made in large quantity. The oil of wintergreen is obtained from the well-known wintergreen plant. Probably all of you have picked and eaten the leaves and berries of this plant, and you, therefore, are familiar with the taste and odour of the oil. This oil, with exactly the same taste and odour as that obtained from nature, can be made in the laboratory. It is related to salicylic acid, which is now extensively used as a medicine. This acid was formerly made from the oil of wintergreen, but it is now eaeily made from carbolic acid and carbonic acid, one of which substances is obtained from coal tar, and the other«from marble or limestone. From salicylic acid the oil of wintergreen is obtained without serious difficulty. A third substance with a decided taste of its own, made from coal tar, is that remarkably sweet compound known as saccharin. This is not at all related to ordinary sugar, but it has the same sweet taste. A given quantity of it has about three hundred times the sweetening power of sugar. A minute particle, which you can hardly see, put on the tongue fills the whole mouth with an intensely sweet taste. It was thought at one rime that this substance might come into use as a sweetener, but there is some question as to whether it is harmless or not and it is not used as much as was expected. I might tell you of many more interesting things made from coal tar, but my story must be a short one, and I want to say a few words about some other things before I stop. The name vanilla will probably suggest ice cream to most of you. But what is vanilla ? It is a substance which is found in nature in a bean known as the vanilla bean. It has long been used as a flavour. It is now manufactured, and the artificial substance is probably used as much as the natural. It can be made from some of the substances found in coal tar, but it is made more cheaply from a substance found in creosote which is obtained from the tar formed when beech wood is distilled. Beech tar and creosote are as disagreeable in their way as coal tar and carbolic acid are in cheirs, but by the fairy wand of chemistry they can be made to yield substances with the most attractive properties. Many other flavours besides those which I have mentioned are now made in the chemical factory. The flavours of most fruits are due to the presence of substances well known to the chemist, and whenever it is possible to make any of” these substances more cheaply in the factory than they can be obtained from nature, they are manufactured. Many fruit flavours, such as those of the apple and pineapple, are thus manufactured.

The oil of mustard is made by starting with ordinary glycerine and oxalic acid. The oil of garlic and many other disagreeable smelling substances which are found in nature can also be made in the laboratory. Among the most disagreeable of these is one called mercaptan. The chemist, who first made this substance and studied it, had to shut himself up in his laboratory for weeks until his work was done. His meals were passed in to him. He at first tried to go among people as usual, buthis clothing was so disagreeable that people got out of his way. It is believed that the fearful odour produced by the skunk is due to a substance something like mercaptan. The liquid of the skunk was once carefully examined by a chemist, but, after working with it for some time, he found that he did not have enough of it to finish the work, and no one has ever taken it up since that time. Here is a fine opportunity for an ambitious young chemist to distinguish himself. Who will take advantage of it? Only a very few of the substances made in the laboratory can be used as dyes or flavours or for any other practical purpose, but the fact that a substance cannot be used practically does not make it any the less valuable to the chemist or to the world. Every substance helps us to know more of the mysteiies of nature, and the more we know the better we are off. We, of course, hear more of those things which are used out of the laboratory, but these things which are of greatest interest to the chemist are those that tell him most of chemistry, and those are, for the most part, unknown to the world at large.