This is a suit for specific performance under an agreement for the sale of real estate, made between the plaintiff as vendor and the defendants as vendees. The agreement of sale provides in part as follows:
"2. Settlement is to take place at Chelsea Title and Guaranty Co., Atlantic City, N.J. on or before the 20th day of August, 1948, at 2 o'clock P.M., D.S.T. which time is of the essence of this agreement, when the Seller shall deliver a plain warranty deed for the said premises, and the balance of the purchase price is to be paid or secured as follows: Six thousand seven hundred and fifty Dollars ($6750.00) cash on day of settlement."
The agreement further provides as follows:
"4. The title to be delivered shall be a marketable title and shall be free and clear of all encumbrances including municipal liens and assessments and liability for assessments for improvements now constructed (except as herein stated), this clause to be operative as of the date of this agreement, and the title is to be subject to all existing restrictions of record, the seller, however, guarantees that there are no restrictions in any conveyance or plans of record affecting the said premises, which will prohibit the use and/or occupancy thereof as an apartment house building or for the construction of a three story apartment building containing more than 3 apartments, and the premises shall be conveyed in the same condition as the same now are, reasonable wear and tear excepted."
On August 5, 1948, the vendor signed the following letter which was prepared by Clarence Blitz, Esquire, counsel for Aaron Sherman:
"Clarence Blitz, Law Offices, Atlantic City, N.J.
To Max Perkins, Vera Perkins, his wife and Aaron Sherman
This is to advise you that I agree as Seller of premises described in an agreement entered into between you and me on August 2, 1948, to postpone the date of settlement from August 20, 1948 at 2 o'clock p.m. D.S.T. to be had on or before November 15, 1948. This may be attached to and become a part of aforesaid agreement.
Thereafter, under date of September 22, 1948, Clarence Blitz, Esquire, counsel for Max Perkins and Vera Perkins, addressed and mailed the following letter to the plaintiff:
Clarence Blitz, Law Offices, Atlantic City, N.J.
Chelsea Title and Guaranty Co. has set aside November 15, 1948, at 2 p.m., at the Title Company, Boardwalk National Bank Building, Atlantic City, N.J., as the time and place for the settlement of the property on Providence Terrace, Atlantic City, N.J. under contract of sale by you to Max Perkins, Vera Perkins, and Aaron Sherman.
Kindly advise in the enclosed self-addressed envelope if the date is agreeable.
In response to this letter the plaintiff mailed the following letter to said Clarence Blitz:
"Hoffman Bros., Jewelers, 1503 Atlantic Avenue,
606 Schwehm Bldg., Local.
In reference to your letter of Sept. 22nd wish to state that Nov. 15th 1948 will be ...