Bakclax, J.
The suit is in equity bytrusteesunder the will of Mr. Joseph J. Mersman to have instructions from the court as to their powers and duties. All the parties interested were brought into the case. The trial court entertained the petition and construed the will, after a full hearing.
In the statement opening the report of the present appeal, appear the important parts of the document to be construed, and also a short description of the other portions of it.
There are two groups of beneficiaries, one group asserting a certain meaning of the will, and the other denying it. The substance of the claim of the first group is that the homestead premises (described in section 10 of the will) should be sold and the proceeds invested in other property, subject to the same conditions and rights of occupancy. They insist that the three beneficiaries (authorized to occupy the old home*255stead) are entitled to exercise the choice above indicated, and that by reason of the tendency of said real property to depreciate in value, and for other reasons, the best interests of all concerned would be subserved by a sale outright of that property and a re-investment of the proceeds elsewhere on the same limitations.
The other group of interested parties combat the above theory.
In view of the controversy as to what should be done, the testamentary trustees came into court, asserting that they were in doubt and uncertainty as to the true interpretation of the terms of the trust, and desired the advice of the court.
The various parties to the difference then stated their positions in a series of pleadings that need not be further noted.
The real gist of the whole dispute is found in the inquiry whether the will expresses an intent to give the three beneficiaries, Frederick, Ella and Emma, named in the tenth section, a home generally out of this property (or its proceeds) or, on the other hand, an intent to give them only the use of the old home itself during their lives, or so long as they choose to occupy it.
The learned circuit judge found in favor of the latter construction. The other side then appealed to the supreme court in the ordinary way.
It appeared at the trial that the testator at the time of his death (March 26th, 1892) occupied as a residence and homestead a house and lot on the corner of Ken-nett Place and Mississippi avenue, near Lafayette Park, in St. Louis; that five of his eight children, to-wit: Otto, Joseph, Arthur, Alice, and Clara, had married before testator’s death, and were not living on said premises, while Frederick, Ella, and Emma, all *256adults, were living with their father at the time of his death, and were residing in the homestead at the time of the trial. The three children last named are those mentioned in the tenth clause. That clause or section and the nineteenth contain (as all parties concede) the language which has given the trustees their difficulty, and which the courts are called upon to aid them to construe.
1. Such a bill in equity is undoubtedly maintainable by testamentary trustees to settle questions such as that before us, involving reasonable grounds for doubt and uncertainty on their part as to the execution of their trust. 27 A. & E. Encycl. L. (1st ed.) “Trusts and Trustees,” p. 151.
2. The sound interpretation to be given a'will is that which truly unfolds the intention of the testator as expressed within the four corners of the instrument. In getting at that intent it is not permissible to introduce outside testimony of declarations, etc., to show the mental purpose or design of the testator on the point of controversy. If he was so unfortunate as to intend one thing, and yet declare the opposite by the terms of his formal and final expression of intent, then the latter must ordinarily control. At least, there is. nothing before us in the case at bar to prevent the application of that rule. So the learned trial judge was right in rejecting the testimony tendered to show the personal intent of the testator, on the point of the present controversy, as distinguished from the intent, which the will exhibits on that point.
3. The general power to sell, etc., and to re-invest,, as given by the nineteenth clause or section of the. will, does not indicate any intent to sanction or permit a sale of the homestead for re-investment in other similar property to be used as a home by Frederick, Emma, and Ella in lieu of the old homestead. Their present. *257interest in equity in that property certainly amounts to nothing greater than a qualified life estate. That sort of a limited estate (and it is not needful to attempt any more specific classification of it) certainly was not designed by section nineteen to be the subject of sale and re-investment by the trustees at the mere election of Frederick and his two sisters. After the expiration of the use of the old homestead (by the three children named) that property is to be sold and the proceeds divided among all the children, according to the closing lines of the tenth clause. That provision plainly discloses that the homestead is not one of the ‘ ‘particular properties set apart” to any of the several children, as described in tjie nineteenth clause.
There is nothing inconsistent between the execution, exactly as written, of the plan laid down by section 10 as to the homestead, and the due execution of the powers conferred by the nineteenth section. Wide and general expressions of a purpose or a power in such an instrument are not to be understood as applicable to special facts and circumstances of a particular property the disposition of which is minutely provided for by another clause of the instrument. We must not wholly eliminate section 10 in considering section 19.
The primary and definite intention as to the homestead is found in the tenth section, and there is nothing elsewhere in the will that manifests a different purpose as to that property.
One rule of great force in solving the difficulties of interpretation is that all parts of an instrument should be read so that they shall stan'd rather than that any part should perish by construction. And to give effect to all parts, the general words of one part may sometimes require to be limited in their application.
In the case at bar one of the beneficiaries under the tenth section had a specific house given her by the *258ninth section which also recited that another beneficiary under the tenth section had already received a like house by deed of gift during her father’s lifetime. The re-investments authorized by section nineteen 'were surely not intended to give Emma or Ella other houses in lieu of the homestead in which they were privileged to reside. There is nothing in that section inconsistent with the provisions of the tenth section which intended, we think, to give a license to the three children mentioned to remain in the old home during life, or so long as they elected to do so.
7. The trial court excluded offers of testimony designed to show that the homestead property had depreciated since the testator’s death; what were the incomes (at the time of the trial) of the three beneficiaries named in the tenth section; what was the cost of maintaining the property as a home; and what par- • ticular affection the father exhibited to his other children.
All those offers were excluded, and the several rulings are assigned as errors.
It is often useful to bring into view, as an aid to construction of any doubtful passage in a will, the circumstances of the testator, so that the court may have the light afforded by the situation in which he was placed when he expressed himself in the document. But there can be no error in excluding such evidence when there is really nothing doubtful to construe in the paper, so far as concerns some controverted point.
Indeed it is very questionable whether any of the offers above mentioned would be admissible, as within the scope of the general rule above stated. Perhaps the item as to his affection for hi.s children might be held a “circumstance” of the making of the will; but we fail to see how its exclusion could be in any wise important or harmful in its bearing on the rights of *259the appellants. Affection for all his children is plainly manifest throughout the will, and all differences in his gifts to them are explained, directly or inferentially, as justified by his prior dealings toward them, or by the circumstances in which they were placed at the time the will was drawn. There was no prejudicial error (that we recognize) in the exclusion of any of those offers of proof.
8. Each will is to a great extent its own interpreter for all the canons of construction are merely aids to reach the true intent of the whole document itself.
9. We consider that the learned trial judge in the ease at bar took a correct view of the meaning of the will. Accordingly the judgment is affirmed.
Beace, C! J., and Macfaelane and Robinson, JJ., concur.