Rocks of the Florida Reefs. 59 



In a quantitative analysis by Homer, and another by Mari- 

 ner, the following results were obtained : — 



The total loss by prolonged ignition, included organic mat- 

 ter, water as hydrate of lime, and carbonic acid, was as fol- 

 lows : — 

 I. 2-7875 gr. lost 1-2687 gr. II. 0-5910 gr. lost 0-2600 gr. 



The water was determined in a chloride of calcium tube, 

 with the aid of a low red-heat and an aspirator. (A heat of 

 175° C. in an oil-bath, expelled but a very small proportion 

 of the water.) 



I. 0-7519 gr. lost 0-0259 gr. II. 1-2890 gr. lost 0-0280 gr. 



The organic matter was determined by washing on a dried 

 filter the hydrochloric acid residue. 



I. 1-7181 gr. gave 0-0028 gr. II. 0-4461 gr. gave 0-0021 gr. 

 The carbonic acid was determined in an evolution flask 



glass. The results with different specimens varied greatly, 

 and are far from being satisfactory. 



I. 0-8605 gr. lost 0-3347 gr. III. 0-1720 gr. lost 0-0585 gr. 



II. 0-1745 gr. lost 0-0600 gr. IV. 1-6116 gr. lost 0-6277 gr. 



The lime was precipitated as oxalate and weighed as car- 

 bonate. 



I. 1-3248 gr. gave 1-2581 gr. II. 0-2550 gr. gave 0*2330 gr. 



The silica was determined in the usual way. 



I. 1-3245 gr. gave 0-0002 gr. II. 0-3760 gr. gave 0-0005 gr. 



The chlorine of the chloride of sodium was determined as 

 chloride of silver. 



I. 0-8933 gr. gave 00303 gr. II. 0'6850 gr. gave 0-0101 gr. 



Expressed in per-cents. we have : — 



Volatile Matter from . 43-99 <f> cent, to 45'51 <f> cent. 



2-17 ... 3-44 



Water 

 Organic Matter 



Carbonic Acid 



Lime 



Chloride of Sodium 



Silica 



0-16 



34-01 



34-38 



51-17 



0-04 



0-01 



.. f38- 

 .. \38- 



0-47 



89 



94 



53-12 



004 



0-01 



It is conceivable that the variabilitv in the carbonic acid 



