[BARNES & COOKE] THE DENSITY OF ICE 155 
From a careful study of the large amount of data available on the 
density of ice, it is evident that this is subject to real variations as 
Nichols suggested and partially showed in his work. These variations 
are, we believe, due to the manner of formation of the ice and are the 
result of strains set up in the ice during formation. That such strains 
disappear in time and that the ice approaches a limiting value seems 
probable. This has been already indicated in Nichols’ work, who 
actually observed a change in density in an ice mantle which had been 
allowed to stand. Experiments are in progress in this laboratory to test 
this point, and it is hoped further results may be communicated later. 
In our historical references we have made constant use of the 
valuable resumé of the subject contained in Nichols’ paper. 
BIBLIOGRAPHY. 
Boyle’s Works (Edition of 1772, Vol. II., p. 551. 
Gehler, Physikalisches Worterbuch, Vol. III., p. 113. 
Pinkerton’s Voyages and Travels, Vol. I., p. 573. 
Williams, Gothaisches Mag., Vol. VIII., p. 176. 
Th. Thomson, A System of Chemistry (Edinburgh, 1802), Vol. II., p. 167. 
Heinrich, Bayerisches Akad., Vol. II., p. 149 (1806), and Gilbert’s Ann. 
Volk XSOViE, pe 228) 807). 
Berzelius, Lehrbuch der Chemie (Wôhler’s translation, 1825), Vol. I., p. 364. 
Dumas, Traité de Chemie, Vol. I., p. 19. 
Dufour, Comptes Rendus, Vol. L., p. 1039. 
Bibliotheque Universelle, June (1860). 
Archives des Sciences, Vol. VIII., p. 89 (1860). 
Comptes Rendus, Vol. LIV., p. 1079. 
[Archives des Sciences, Vol. XIV., p. 5 (1862). 
Brunner, Pogg. Ann., Vol. LXIV., p. 113 (1845). 
Plücker and Geissler, Pogg. Ann., Vol. LXXXVI., p. 265. 
Kopp, Ann. der Chem., Vol. XCIII-, p. 129 (1855). 
Bunsen, Pogg. Ann., Vol. CXLI., p. 1 (1870). 
Osann, Kastner’s Archiv., Vol. XIX., p. 100. 
Heinrich, Gilbert’s Ann., Vol. 26, p. 228. 
Forbes, Glacier Theory, Edin. Rev. (1842). 
Petzholdt, Beiträge zur Geognosie von Tyrol (1843). 
Achard, Chem.-Phys., Schriften (Berlin, 1780). 
Mussenbrek, Essai de Phys., Vol. I., p. 144 (Leyden, 1739). 
Struve, Pogg. Ann., Vol. LXVI., p. 298. 
Marchand, Journ. f. prakt. Chemie, Vol. XXXV., p. 254. 
Nichols, Phy. Rev., Vol. VIII., p. 21 (1899), and Vol. VIII., p. 184 (1899). 
Barnes, Phys. Rev., Vol. XIII., p. 55 (1901). 
Vincent, Proc. Roy. Soc., Vol. LXIX., p. 422 (1902). 
