COVERING SAND DUNES ON THE SEA COAST. 177 



front of this place a palisade of planks is erected par- 

 allel to the shore, about 300 feet distant from the high- 

 est water-mark. The planks, from seven to eight feet 

 long, are sunk in the sand to a depth of about 18 inches, 

 a space of one inch being left between them. The sand 

 arrested by the palisade forms, in due time, an artificial 

 dune, sloping towards the sea, with the destination to 

 prevent fresh arrivals of sand from being blown over 

 the place to be cultivated. The sand which passes 

 through the interstices of the palisades, banks up behind 

 them, and strengthens the sand wall. When the pali- 

 sades, in this way, are nearly covered on both sides, the 

 planks are, with the help of a lever, lifted up, so as to 

 keep them about six feet above the surface, and thus the 

 protection against wind and sand is made permanent. 

 Sometimes a fence, made of eight feet long stakes, be- 

 tween which strong but flexible twigs and boughs are 

 interwoven, is substituted for the wooden palisades. As 

 soon as the accumulated sand has nearly reached the 

 top of the fence, the stakes are raised by a lever and 

 interlaced again. These fences, however, are only in 

 less exposed situations employed instead of the planks, 

 2. Thereupon the place to be worked is enclosed, at 

 the other three sides, by wattled fences. Leaving a 

 space, three yards wide, next to the back fence un- 

 touched, owing to the fact that this space will soon be 

 oversanded by the winds blowing from inland and, there- 

 fore, unfit for plant vegetation. In distances of ten feet, 

 parallel with the back fence, towards the sea furrows are 

 opened, eighteen inches wide and twelve inches deep, in 

 the midst of which the seed of the maritime pine — a 

 variety of piniis silvestris — is drilled and covered with a 

 little sand, mixed with powdered artificial manure. At a 

 distance of eight inches from the middle drill, another 

 drill is made, at each side, in one of which is sown sand- 



