426 ON THE FORMATION OF ICE 



A 



Horner in tlie Dictionnaire de Physiqne of Gclilen, 111, 127; by Arago, [An- 

 nuaire du Bureau des Longitudes 2your 1833,) and by L. F. Koemtz, [Dictionnaire 

 Encyclope digue des Sciences et des Arts, pablished by Ersch and Gruber.) 



The physicist Plot appears to have been the first to make mention of the ice 

 formed at the bottom of rivers, in his "Natural History of Oxfordshire," 1705. 

 Hales, in his "Vegetable Statistics," Loudon, 1731, mentions the existence of 

 ice at the bottom of water as having been ascertained by bargemen, and reports 

 his own observations. He had seen ice of spongy consistence form at the bottom 

 of the river, and remarked that " the water must be in motion in order to have 

 sunk to zero throughout its mass," and he pointed out the influence of asperities 

 and projecting bodies on the formation of this ice. 



Nollet, in 1743, thought the phenomenon incompatible with theory, and com- 

 pletely denied it. Mairan and several other physicists of the epoch shared his 

 opinion. 



Nevertheless, Desmarest, in the Memoirs of the Academy for 1776 and the 

 Journal de Physique for 1783, t. iii, verified anew the formation of ice at the 

 bottom of rivers ; it was afterwards confirmed by Braun, Hanvbrisclies Maga- 

 ziv, 1783, and Journal de Physique, 1788; also by Leslie and by Garnet. lu 

 1806 observations were made by Knight on the Teirie. Stencke, chief of the 

 pilots of Pillau, (Prussia, on the Baltic,) reports in Gilbert's Annalcs de Physique, 

 XX, 332, that, on the 9th of February, ISOC, at a temperature of — 32|- degrees 

 of Fahrenheit = — 35.11 degrees centigrade, chains 12 feet in length surrounded 

 with ice were brought to the surface of the water from a depth of 12 to 15 feet, 

 as well as a large cable 30 toises long, which had been immersed for a consid- 

 erable time. 



On the 11th of February, 1816, the abbe Branthoma, then jivofessor of chem- 

 istry in the Faculty of Sciences of Strasbourg, again verified the formation of 

 ice at the bottom of the bed of the Rhine, in presence of the engineers of bridges 

 and roads. The temperature of the air was at 12° ; the Ehine, at the place 

 where the ice formed, was about 2 metres in depth. The ice was seen to form 

 very perceptibly at the bottom of the water, not only at this point, but at many 

 others. The thermometer was at zero at the surface of the water, while another 

 thermometer introduced into the ice was equally at zero. When taken from the 

 water the ice had the same temperature, was very porous, and formed of inter- 

 lacing crystals. Towards 10 o'clock the ice, having become more compact, was 

 detached from the bottom, and rising floated on the surface. [Bibliotheque Uni- 

 verselle, xvii, p. 304.) 



In 1827, Merian observed, at Bale, ice at the bottom of the water in the canal 

 of Saint Alban. Li the same year Hugi made a great number of observations on 

 the spongy ice formed at the bottom of the Aar, near the bridge of Soleure. 

 The very cold winter of 1829 led to the first observations which 1 made at Zins- 

 weiler, (Lower Ehine,) and df which I gave notice, the same winter, to the 

 Society of Natural History of Strasbourg, then recently instituted.* 



M. Fargeaud, professor of physics, published, in 1830, his thesis on caloric, 

 in which he communicated his observations on ice thus formed, in the following 

 terms : " On Sunday, January 25, 1830, I happened to be present with several 

 of my pupils on the bank of the Rhine, opposite to Kehl. A thermometer, sus- 

 pended to a tree, indicated 31° Reaumur; while another, placed in the snow at 

 an inch from the soil, stood at nearly 6° Reaumur. Notwithstanding this great 

 degree of cold, the water which flowed in the moat of the citadel was frozen 

 only on its borders. That part of the bed of the Rhine which by an embank- 

 ment of sand was sheltered from the wind, was also destitute of ice. At the 

 same tune the thermometer resting on the surface of the water rose rapidly to 



* This society was founded in December, 1828, by certain members of the Society of 

 Sciences, A.gricultnre and Arts of the Lower Ehine, viz. , MM. Boeckel, Duverno}-, Ehrmann, 

 Engelhardt, Fargeaud, Lauth, Nestler, Silbermann, and Voltz. 



