Prof. A. D. Bache on Tidal Obsc?'vaiio?is, 341 



-t 



green when cold; in the reducing flame, while hot, color not 

 so deep as in the oxydating flame, and passes throngh the shades 

 of olive green while coohng, to beafitiful emerald green when 

 cold. With phosphate of soda and ammonia in the oxydating 

 flame, dissolves slowly, leaving a skeleton of the fragments ; 

 glass red and yellowish while hot, fine green when cold. When 

 much of the assay is added, the glass becomes opalescent to 

 opaque when coohng; in the reducing flame, skeleton disap- 

 pears, bead brown while hot, opalescent and green while cold. 

 With carbonate of soda on platina foil, no reaction for manganese. 



The constituents of the mineral so far as indicated by the above 

 reactions are, B[, Si, Sr, Pe. Analyses are now in progress at the 

 Yale Analytical Laboratory, 



In addition to the optical character, the mineral is shown to 

 differ from chlorite in hardness and elasticity, and by the pres- 

 ence of chromium. 



1 propose for the species the name ClinocJilore^ in allusion to 

 the great obliquity between the optic axes^ and its green color 

 resembling that of chlorite. 



A similar mineral from Unionville occurring in triangular and 

 hexagonal forms, I have fomid to be biaxial and probably like 

 the above ; but I have not yet succeeded in obtaining any meas- 

 urements. 



Art. XXXY. — Notes of a Discussion of Tidal Observatio?is 

 made in &Sn7iection with the Coast Survey, at Cat Islaird. in 

 the Gulf of Mexico; by Prof. A. D. Bache, Superintendent* 

 ^ith five plates. 



In executing the hydrography of the entrance of Mobile Bay 

 and of Mississippi Sound, connected tidal observations were made 

 tinder the immediate direction of Lieut. Comd'g. C. P, Patterson, 

 U. S. N., Assistant in the Coast Survey. 



The observations at Cat Island, at the entrance to Lake Borgne, 



L 



Bay 



"-ive undergone more than one discussion, the peculiarities oi tne 

 tides giving great interest to the observations. 



1'he resuhs, as obtained from a year's hourly observations day 

 and night at Cat Island, will be given as far as obtained, the steps 

 taken for further progress stated, and the information which has 

 been obtained from other sources bearing tipon this most interest- 

 ing problem of the tides in the Gulf of Mexico, will be briefly 

 touched upon. 



* From the Proceedinics of the American Association for the Advancement of 

 Hcience, 4th meeting at New Haven, 1850, p. 281. Revised by the autlior for this 



Seeies, YoL XII, No. 36,— Nov., 1851. 44 



BO 



