PRESCRIPTIVE RIGHT OF WAY. 159 



To gain this right by twenty years' use, it is not necessary 

 that any one owner should have travelled it twenty years. 

 If successive owners have unitedly used it for that period, it 

 would be sufficient, so far as length of time is concerned 

 (2 Allen, 277). And if this prescriptive right of way was 

 gained only by using it for some particular purpose, as for 

 carting wood from a wood-lot beyond, that would not author- 

 ize the person to continue to use it for all purposes, after 

 the wood had been all cut off, and it had been covered over 

 with buildings (11 Gray, 150; 15 Gray, 387). 



3d, The third mode, by necessity, arises when you sell a 

 man a back lot, with no means for him to get to any high- 

 way except over your remaining land. The law gives him 

 a right to cross your land to and fro : otherwise his land 

 would be useless. At present he can't reach it by balloon 

 to any practicable purpose, and therefore he must cross your 

 land. So, if you sell a man all your front land, retaining the 

 back part, and have no way out except over the part sold, 

 you retain a right to cross the lot sold, though your deed in 

 such case says nothing about it ; and this is so, even if in 

 your deed you warrant the land to be free and dear from all 

 incumbrances (4 Gray, 297). It is a familiar maxim that 

 " necessity knows no law." 



But this right of way by necessity continues only so long 

 as the necessity itself continues ; and if a highivay is after- 

 wards laid out touching the back land on the other side, or if 

 the owner afterwards buys a lot adjoining it and between it 

 and a highway, he can no longer cross over your land as 

 before, but must go out the other way (14 Gray, 126). And, 

 so long as he does have such a right, he must go in such 

 place as you designate, if it be a reasonable place. If you 

 mark out a road or a way along the fence, or on the poorer 

 ground, he should confine himself to that (2 Pick. 478). 

 And, if the way becomes miry or out of repair, he must keep 

 it in good condition if he wants to use it. Your duty is 

 done when you allow him to cross : you are not obliged to 

 smooth his pathway for him, and rake out the sticks and 

 stones (12 Mass. 69). But if you actually obstruct his usual 

 road, or if it becomes suddenly impassable by natural causes, 

 he would have a right to deviate to one side until he has 

 opportunity to remove the obstructions (2 Allen, 546). 



