REPORT OF THE CHIEF ASTRONOMER 659 



SESSIONAL PAPER No. 25a 



Steinmann has made important experiments which tend to corroborate 

 some of the main conclusions of Murray and his colleagues. He added decaying 

 albumen to solutions of calcium chloride and found that calcium carbonate, in 

 the form of round, minute bodies like coccoliths, was precipitated. This result 

 raises the query whether many of the coccoliths described as occurring in deep- 

 sea sediments are not direct witnesses to an actual chemical precipitation of 

 calcium carbonate on a large scale over much of the sea floor. 



Irvine and Woodhead have shown conclusively that marine animals, even 

 those normally secreting limey structures, will live and comparatively thrive in 

 sea water from which every trace of calcium carbonate has been eliminated.! 

 In one experiment they mixed sodium chloride, magnesium chloride, magnesium 

 sulphate, calcium sulphate, and potassium sulphate with pure water in about 

 the proportions of average sea water. In this artificial sea water (No. 1) they 

 placed a number of crabs. In their proper seasons the exoskeletons were shed 

 but were never rebuilt by the animals. Yet the crabs continued to feed and 

 live, long after the exfoliation had taken place. 



In a second experiment -0903 per cent by weight of calcium chloride was 

 added to No. 1 water, giving No. 2 water. In this the crabs lived and rebuilt 

 their exoskeletons. This new structure was composed of the carbonate and 

 phosphate of lime and chitinous matter in the proportions present in normal 

 shells. Other crabs similarly throve in a third water in which the calcium 

 chloride in average sea-water proportion was substituted for the calcium sul- 

 phate of No. 1 water. 



The proof is clear that the secretion of calcareous structures is by no means 

 dependent upon the presence of calcium carbonate in sea water. 



In a fourth experiment sodium chloride and magnesium chloride were 

 dissolved in pure water in the proportions of average sea water. Crabs and 

 fish were found to thrive in this water, ' feeding greedily, but of course ecdysis 

 (elaboration of cast exoskeletons) in such water was impossible.' Ecdysis was, 

 however, carried out when calcium chloride was added to the solution. 



The whole series of experiments cited indicate the possibility, first, that the 

 ^•re-Cambrian ocean could hold but a minute quantity of lime salts in solution 

 unless those salts were being continually and largely fed into the sea and pre- 

 ferably fed at the surface, farthest from the bottom stratum of water charged 

 with the products of decaying animal matter; and, secondly, that abundant life 

 existed in water so nearly limeless. 



OBSERVATIONS ON THE BLACK SEA. 



The well known, remarkable studies of Andrussow and others on 

 the hydrography and deposits of the Black Sea show that we have 

 in a large existing basin a strong analogy to the imagined Eozoic 



t R. Irvine and G. S. Woodhead, Proc. Eoyal Society, Edinburgh, Vol. 16, 1889, p. 

 324. _ ,j 



25a — vol. iii — 43 



