Januabt 15, 1904.] 



SCIENCE. 



93 



Meissner, hydrochloric acid is composed of 

 two equivalents of oxygen, one of water, 

 combined with ai-aeon and the imaginary 

 radical murium (vide Bolton). Often al- 

 loys have been prepared and given names 

 like the elements, 'magnalium,' for exam- 

 ple. These are omitted also. - Otherwise, 

 I have purposely included every sugges- 

 tion of an element I could obtain. The 

 summary, while doubtless deficient, may 

 secure an historical vindication. 



What shall we do with these numerous 

 aspirants whose recognition is urged? 

 "These elements perplex us in our re- 

 searches, baffle us in our speculations and 

 haunt us in our very dreams. They stretch 

 like an unknown sea before us, mocking, 

 mystifying and murmuring strange revela- 

 tions and possibilities. ' ' said Crookes, refer- 

 ring to the rare earths. Some have been 

 verified, many unverified; some are true, 

 some are false. Without doubt some have 

 been presented without sufficient stage set- 

 ting, yet the good faith of many can not be 

 questioned. In fact, from this list, as one 

 reads, he perceives the whole gamut of sci- 

 entific emotions. There he may find the 

 tragedies of elemental pretension, the com- 

 edies, yea, the very farces. 



We need not look far to ascertain expla- 

 nations for certain incorrect conclusions. 

 The extreme rarity of the minerals in which 

 many of the tentative elements have been 

 detected, the excessively small percentages 

 of the new ingredients, and the extraor- 

 dinary difficulties attending their separa- 

 tion from known and unknown substances 

 combine to render the investigations labori- 

 ous, protracted and costly. De Boisbau- 

 dran required 2,400 kilograms of zinc 

 blend for 62 grams of gallium. Ramsay* 

 has shown one part of crypton in twenty 

 million volumes of air, while a like amount 

 of xenon requires one hundred and seventy 

 million. How patiently and persistently 



* Zeit. phys. Ghem., 44, 74, 1903. 



that modest Parisian couple followed Bec- 

 querel's rays! 



Furthermore, when one feels that he has 

 obtained something novel, the absolute 

 proof is fraught with difficulties and un- 

 certainties. We have decided to define an 

 element by its properties. The alterations 

 produced in the properties of the most char- 

 acteristic elements by the presence of small 

 amounts of foreign substances are evident 

 in steel. The influence of arsenic upon the 

 conductivity of copper is well known, and 

 Le Bon* has recently shown that traces of 

 magnesium (one part in 14,000) in mer- 

 cury cause the latter to decompose water 

 and to oxidize rapidly in the air at ordinary 

 temperatures. Thorium with less than a 

 trace of actinium produces an auto-photo- 

 graph. 



This point can not be too strongly 

 stressed in the rare earth field. One who 

 has wrought with thorium dioxide well 

 knows the influence a small amount of 

 cerium has upon its solubility. The con- 

 flicting statements in the literature as to 

 the colors of the oxides of the complexes, 

 neodidymium and prseseodidymium, cause 

 one to wonder if difl:erent researchers have 

 had the same hscceity. 



An appeal to the spectroscope is of course 

 in the minds of all my hearers. 



It was once supposed that each element 

 has its characteristic spectrum which re- 

 mained the same under all circumstances. 

 Keelerf calls attention to modern investiga- 

 tions which have shown that the same ele- 

 ment can have entirely different spectra. 

 For example, oxygen may be caused to have 

 five different spectra; nitrogen, two, etc. 

 In fact, there is no indication in the appear- 

 ance of the spectra that they belong to the 

 same substance; yet through the result of 

 the work of Rydberg, Kayser, Runge and 



* Compt. rend., 131, 706, 1900. 

 t Scientific American Supplement 88, 977, 1894, 

 and Popular Astronomy. , 



