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SCIENCE 



[Vol. LV, No. 1417 



the Chevalier Philippe de Fay, the truest of 

 Dolomieu's friends, to Picot de la Peyrouse, 

 botanist and geologist of Toulouse, to the great 

 geologist Saussure, to the Genevan physician 

 Pictet, to Pierre Picot, professor of theology in 

 Geneva, and to Frederic Munter, professor of 

 theology in Copenhagen. 



The following extract from a letter to this 

 last named correspondent, is a eharaeteristie 

 example. Dolomieu, after passing safely 

 through the throes of the French Revolution, 

 was appointed, in 1796, lecturer in geology and 

 the distribution of minerals at the newly- 

 organized Ecole des Mines. A year later, Jan. 

 15, 1797, he writes to his friend Munter :i 



"The sciences, which were for me formerly a 

 relaxation, have become a profession which fur- 

 nishes me the means of livelihood, and none the 

 less I cultivate them with pleasure. I am chiefly 

 occupied with mineralogy and geology, and I 

 give lessons in these branches at the Eeole des 

 Mines during the winter. During the summer 

 I travel to inspect the mining operations. I 

 have assumed charge of the mineralogical ar- 

 ticles of the Dietionnaire Encyclopedique, and I 

 write articles which are published in various 

 journals. Thus I employ my time in a manner 

 agreeable to myself and I advance without much 

 disquietude toward that fatal term against 

 which aU human hopes make shipwreck. We 

 have become so accustomed to the idea of death, 

 that we now see our last hour approaching with 

 complete indifference." 



The biographical sketch already noted is re- 

 printed by Professor Laeroix at the beginning 

 of the first volume of the present work (pp. i — 

 Ixsx). To this succeeds the unique recoi'd writ- 

 ten by Dolomieu in 1799, in his prison at Mes- 

 sina, where he was incarcerated because of his 

 supposed guilt, as a Knight of Malta, in aiding 

 Bonaparte to seize the island. It was inscribed 

 on the margins of the leaves of a book he had 

 succeeded in obtaining, and which is now a pre- 

 cious possession of the Museum d'Histoire 

 Naturelle (pp. 1-44). The quality of this rec- 

 ord may be exemplified by the following brief 

 extract : 



"My passion for the phenomena of Nature 



1 Vol. II, p. 138. 



was so strong that every year, when spring 

 renewed the life of the vegetable kingdom and 

 gave new force to all organized beings, the 

 environs of Paris seemed too restricted for mo, 

 its atmosphere heavy and offensive .... 

 Therefore each year I hastened to the mount- 

 ains, and sought on their summits those pro- 

 found emotions which the contemplation of 

 very great objects always procures us . . . 

 Now, confined within a space of twelve feet 

 long, and ten feet in height and width, I can 

 only contemplate my own wretchedness and 

 reflect upon the vicissitudes of fortune and 

 my strange destiny." 



Fortunately the Italian victories of Bona- 

 parte opened his prison doors, his liberty be- 

 ing prescribed in one of the articles of the 

 peace treaty of Florence, March 20, 1801. 

 However, his enfeebled health did not long 

 permit him to enjoy his recovered freedom. 

 He died at Chateauneuf, November 6, 1801, 

 but fifty-one years old. 



Of Dolomieu's scientific attainments. Pro- 

 fessor Laeroix notes that it was principally 

 in the study of volcanic phenomena that he 

 left his trace, and asserts that by his researches 

 concerning Auvergne, he takes his place in the 

 first rank of those who have recognized and 

 demonstrated the relations existing between 

 volcanism and the internal heat of the earth. 

 George F. Kunz 



SPECIAL ARTICLES 

 DISSOCIATION OF HYDROGEN IN A TUNGS- 

 TEN FURNACE AND LOW VOLTAGE 

 ARCS IN THE MONATOMIC GAS 

 In the course of an investigation of arcing 

 characteristics of diatomic gases being carried 

 on in this laboratory, it was found that the 

 arc between a hot tungsten filament and a 

 plate anode in hydrogen struck and broke at 

 a minimum of 16.4 volts. This potential is 

 about that ascribed ))y Bohr's theory to the 

 potential necessary to accelerate an electron 

 so that it will dissociate the molecule and ionize 

 one of the atoms upon impact. In view of the 

 fact that Bohr's theory puts the ionizing po- 

 tential of the hydrogen atom at 13.52 volts 



