1922.] The Agricultural Value or Sea-Sand. 591 



new ideas before the public aiming at reducing costs — mole 

 ploughs, for example, of smaller bore than those usually em- 

 ployed, designed to be hauled by tractor, and machines of 

 several types designed to cut trenches for tile drains. 



The misfortune of draining operations in the past has been 

 the lack of scientific knowledge of the relative efficiency of the 

 different systems and methods offered to the farmer and the land- 

 owner. Tradition and unsupported theory have too often been 

 accepted as gospel. It is now generally recognised as essential 

 that a scientific system of field drainage must be based, like 

 all other farming operations, upon observation and measure- 

 ment, and that exact knowledge cannot be easily acquired. 

 Already work has been started in several countries and before 

 long it should be possible to prescribe with accuracy the best 

 system of drainage in any given circumstance and to give a 

 substantially accurate forecast of its economic results. 



****** 



THE AGRICULTURAL VALUE OF 



SEA-SAND. 



W, BoRLASE, N.D.A., and 

 Alexander Gregg, B.Sc. (Agric), N.D.A., 

 Agricultural Dept., Cormvall C.C. 



The practice of applying sea-sand to the land is a very old 

 one in Cornwall. The sand contains a large proportion of 

 calcium carbonate from the shells of cockles, limpets, mussels 

 and other varieties of shell- fish which are abundant on the coast. 



Sources of the Sand.— In many places the beach is dry at 

 low water for considerable distances seaward, and a fresh sea 

 breeze will then carry the loose sand inland, and unless its 

 progress is arrested by the cliff or running water it may spread 

 over a large tract. The sand w^ashed up during the period of 

 spring tides may be blown away when left exposed during neap 

 tides. In this way large areas, some of them several square 

 miles in extent, have been covered by accumulations of sand in 

 many districts along the coast, notably at Padstow, Perran Bay, 

 St. Ives Bay and near the Tand's End. The accumulations take 

 the form of low hills and deep valleys or hollows, the hills or dunes 

 being in many places 50 to 60 feet high from base to crest. 

 Buildings have been buried and lost for ages until a removal of 

 the sand by the wind or some other agent has again exposed 

 them. As recently as in 1800 A.D. the sexton and worshippers 



