30. Where a dominant heritage is divided between two or more persons, the easement becomes annexed to each of the shares, but not so as to increase substantially the burden on the servient heritage: Provided that such annexation is consistent with the terms of the instrument, decree or revenue-proceeding (if any) under which the division was made, and, in the case of prescriptive rights, with the user during the prescriptive period. Illustrations (a) A house to which a right of way by a particular path is annexed is divided into two parts, one of which is granted to A, the other to B. Each is entitled, in respect of his part, to a right of way by the same path. (b) A house to which is annexed the right of drawing water from a well to the extent of fifty buckets a day is divided into two distinct heritages, one of which is granted to A, the other to B. A and B are each entitled, in respect of his heritage, to draw from the well fifty buckets a day; but the amount drawn by both must not exceed fifty buckets a day. (c) A, having in respect of his house an easement of light, divides the house into three distinct heritages. Each of these continues to have the right to have its windows unobstructed.