VALUATION OF FERTILIZERS, ETC. 467 



These three deposits of tidal water are of a simihir com- 

 position. The amount of organic matter present does not 

 exceed seven per cent. , and the sohiI)le 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 fol- 

 lowing references are given : — 



Kelp and Rockweed. See Report of State Board of 

 Agriculture, 1878-79, page 347. 



Rockweed and Musselmud. Report, 1879-80, page 

 338, 339. 



Eel-grass. Eeport, 1882-83, page 407. 



Analysis of Soil from a Dik^d Marsh at East Salisbury ^ 



Mass. 



Moisture at 100° C 34.40 



Organic and volatile matter, 92.15 



Ash constituents, 7.85 



Soluble part of ash, 4,20 



Insoluble part of ash, 3 65 



Nitrogen in organic matter, 1.64 



Phosphoric acid in ash, .13 



Potassium oxide in ash, .26 



Calcium oxide, 1.24 



