MAR 



MAR 



MARL. A mixture of earths con- 

 taining a large amount of mild lime. 

 It is clayey or argillaceous when it 

 has the mechanical characters and 

 touch of clay, sandy when silicious, 

 and calcareous when almost entirely 

 composed of mild lime : it is also 

 shelly when full of fossil shells. There 

 is one feature common to all true 

 marls, viz., effervescence with acids. 

 Marl may be derived from ancient 

 formations, more especially the upper 

 red sandstone, but is for the most 

 part of tertiary origin, or modern, be- 

 ing produced in ponds and rivers flow- 

 ing in limestone countries. The rich- 

 est shell kinds are best, as they con- 

 tain bone earth. The value of marls 

 is precisely as the amount of lime 

 they contain. When very rich, they 

 may be burned for quicklime, which 

 much increases their activity and val- 



ue. Marls seldom contain more than 

 twenty per cent, of carbonate of lime 

 associated with sands or clay. They 

 are applied at the rate of fifteen to 

 thirty wagon loads the acre, and do 

 much good by altering the texture of 

 some soils, as when a clay marl is 

 applied to sandy lands. In some ca- 

 ses one hundred wagon loads have 

 been applied. They are chiefly indi- 

 cated where the soil lacks lime, or 

 may be improved mechanically ; but 

 being, for the most part, mineral com- 

 posts, marls arc usually serviceable, 

 and often extremely beneficial, espe- 

 cially to poor, sandy lands. Shell and 

 coral sands are of the nature of si- 

 licious marls, but more active, from 

 containing organic matter. 



The following analysis, by Spren- 

 gel, gives the composition of sever- 

 al kinds of marl : 



The marls are usually applied on a 

 fall fallow, on the surface, and left to 

 crumble during the winter and spring; 

 they are also applied as top-dressings 

 to meadows. 



The quality of any marl is ascer- 

 tained by weighing 300 grains of 

 strong muriatic acid into a flask, 

 and then 100 grains of the marl, add- 

 ing it to the acid carefully in pow- 

 der ; and w-eighing again after all ef- 

 fervescence has subsided, the loss 

 in the 400 grains will be carbonic 

 acid, and is about equivalent to the 

 amount of lime in the specimen, in 

 the ratio of 22 gas to 28 lime. Marl- 

 ing is particularly serviceable for clo- 

 484 



vers, pease, beans, hemp, and pota- 

 toes. 



MARMALADE. A sweatmeat of 

 the pulp of fruit, usually of the peel 

 of oranges. 



MARMORATUM. In building, a 

 cement of pounded marble with lime. 



MARRAM. The sea reed {Arundo 

 arenaria). 



MARROW. The oily fat filling 

 the cavities of the long bones. 

 ! MARSH. A low, partially flooded 

 tract of land overgrown with coarse 

 grasses and sedges. The herbage of 

 salt marshes is often very good fod- 

 der, and regularly cut for cattle. They 

 [ are frequently made available by em- 



