Shaw, C. J.

The question in the present case arises from a reservation in a deed, conveying land to the plaintiff, duly made and executed by the inhabitants of Marblehead. This deed, made in 1839, purports to convey to the plaintiff a tract of land, embracing a line of beach bounding on the sea, and contains the following reservation: “ Reserving to the town the right and privilege to enter on the beach, and to take and carry away gravel and sand therefrom, as the said' town may have occasion, for the making and repairing of their highways,” &c

The action is brought against the defendants, who claim to *576have acted under the authority of the town, and justify their right so to do under the foregoing reservation; and the question is, what is the true construction and legal effect of that reservation ? The averment in the declaration is, that the defendants, instead of taking sand and gravel, took and carried away ballast; and the proof was, that they took up and carried away stones of considerable size, embedded in and mixed with the beach gravel on the sea shore, and that such materials did not come within the description of sand and gravel.

Evidence was offered by the defendants, to prove the meaning of the words “ sand and gravel,” as generally and usually understood at Marblehead; also to prove that the same species of material had been used for the same purpose, before the making of the said deed. The court rejected the former evidence and admitted the latter.

The court are of opinion, that the instructions were right upon both points. As to theirs#, we think the general rule of law is, that the construction of every written instrument is matter of law, and, as a necessary consequence, that courts must, in the first instance, judge of the meaning, force and effect of language. The meaning of words and the grammatical construction of the English language, so far as they are established by the rules and usages of the language, are, prima facie, matter of law, to be construed "'.nd passed upon by the court. But language may be ambiguous and used in different senses ; or general words, in particular trades and branches of business — as among merchants, for instance — may be used in a new, peculiar or technical sense; and therefore, in a few instances, evidence may be received, from those who are conversant with such branches of business, and such technical or peculiar use of language, to explain and illustrate it. One of the strongest of these, perhaps, among the recent cases, is the case of Smith v. Wilson, 3 Barn. & Adolph. 728, where it was held, that m an action on a lease of an estate including a rabbit warren, evidence of usage was admissible, to show that the'words “ thousand of rabbits” were understood to mean one hundred dozen, that is, twelve hundred. But the decision was placed on the ground that the words “ hundred,” *577“ thousand,” and the like, were not understood, when applied to particular subjects, to mean that number of units ; that the definition was not fixed by law, and therefore was open to such proof of usage.

Though it is exceedingly difficult to draw the precise line of distinction, yet it is manifest that such evidence can be admitted only in a few cases like the above. Were it otherwise, written instruments, instead of importing certainty and verity, as being the sole repository of the will, intent and purposes, of the parties, to be construed by the rules of law, might be made to speak a very different language, by the aid of parol evidence. The instruction, in this case, was cautiously expressed and guarded

As to the second, the instruction was sufficiently liberal for the defendants. In a conveyance of title, deeds must be construed according to the language ; and if the town, when they owned the land, took materials not coming within the description of “ gravel and sand,” as they well might do, to mend their highways — as paving stones, or materials for macadamizing — but chose to make their reservation in narrower terms, they must abide by it, and pannot enlarge it by showing such former usage. But, construed according to the subject matter, we are to presume that the evidence was admitted, to operate to this extent only, namely, that it might tend to show that all such material as had been used as gravel, to spread upon the surface of the roads, in the usual mode of covering roads made of earth and gravel only, was in the contemplation of these parties, and, to that extent, to show what they regarded as gravel.

Whether the jury drew the right conclusion from the evi dence, we have no means of knowing; the evidence not being reported. We were referred to the declaration for a description of the material which was actually dug and carried away ; but whether the proof fully came up to the averment, we do not know. This is an action of trespass, and concludes no right. If the verdict was against the evidence, the parties will have an opportunity to test the question again in a new action

Judgment on the verdict