10 



Soluble constituents contained : 



I. II. 



Sesqni oxide of iron, 



Calcium oxide, 



Magnesium oxide, 



Potassium oxide, 



Sodium oxide, 



Phosphoric acid, traces, traces. 



178. BLACK MUD. 



From the flats near We^'mouth, Mass. 



Sent on by Thomas A. Watson, Esq. 



Moisture at 100° C, 56.55 



Ash constituents, 39.60 



Insoluble in acids, 31.84 



Nitrogen in organic matter, 0.30 



Soluble constituents contained : 



Sesqui oxide of iron, 4.26 



Calcium oxide, 0.91 



Magnesium oxide, 0.66 



Potassium oxide, 0.38 



Sodium oxide, 0.86 



Phosphoric acid, traces. 



These three deposits of tidal water are of a similar composition. 

 The amount of organic matter present does not exceed seven per 

 cent. ; and the soluble mineral substances are mainly those found in 

 the water of the ocean. The commercial value of plant constituents 

 amounts at present rates per ton of the deposits, in none of them to 

 more than $1.75 ; in the last named sample still less. 



For those interested in the composition of the fertilizing material 

 deposited and collected along the seashore, the following references 

 are given : 



Kelp and Eockweed. See Report of State Board of Agriculture 

 1878-79 ; page 347. 



RocJiweed and Mtisselmud. Rep. 1879-80 ; page 338 — 33i). 



Eelgrass. Rep. 1882-83; page 407. 



