forms, or conditions, since the appearance and the readily recognizable properties of the three differ widely. That is a bit of chemical reasoning which your friend may or may not understand, but which is valid for us chemists. You may further add that graphite as well as diamond can be prepared from the ordinary carbon, either, as for graphite, in the electric furnace or, for diamond, from the solution of carbon in fused iron. For phosphorus the case would be just as phenomenal, considering the difference of the yellow and the red variety in behavior. Here, however, the transformation of one form into the other is more readily demonstrated. Let us assume (as is probably the case) that for all elements there exist such allotropic forms, where do our terms equality or similarity come in? We must assume such substances as similar (or equal) which, when brought together with a third substance, will produce the same fourth body. Thus, in this case one fact, and this one fact only, will prove similarity or equality. And, finally, we approach those cases which are so abundantly found in organic chemistry and for which we have the term isomerism. Two (or more) substances which are different in all their properties, except in the one that they will yield upon combustion, say, carbon dioxide and water, to the same amount; both are considered as produced from the same ultimate elements. Also here, the one fact of production of a fourth (and fifth) body counteracts all of the other observed facts of dissimilarity and makes the two isomers in a sense equal. And, in case of the existence of hundreds of isomers, all of them, in a sense, would have to be considered as equal or similar. Equal or similar in what? In one case of behavior only. Why is it that this one case of behavior overshadows all of the other cases of dissimilarity? As we stand here before a multiplicity for which wr ignore the real cause, we have attempted to hypothesize a cause, but let that not lead us astray; let us rather state that we have no measure for equality and similarity in chemistry, that we are far from understanding the scope of possible multiplicity in chemical interaction. Percentage of elementary matter which we can get out of a given substance in the form of a new substance, will not tell us anything clear and new about our great variety of isomers. L. H. FRISDBURG 601 W.148Ta STREET, NEW YORXCITY
One o l our correspondentsdesires iniormation relative to John Harrison (1773-1833). one of the earliest manufacturing chemists in the United States. Any suggestions will be appreciated.
