Opinion by
Me. Justice Benjamin R. Jones,This is an appeal from the grant of a preliminary injunction by the Court of Common Pleas of Northampton County, sitting in equity.
Seven school districts in Northampton County (one third class district and six fourth class districts) joined in the formation of a joint school district called the “Northampton Area Joint School District”. Due to an increase in school enrollment the public schools in the area have become seriously overcrowded and approximately 2,000 children are affected by these overcrowded school conditions. For the purpose of building a new high school to alleviate this situation, on August 23, 1956 the seven school districts and a joint school district comprising all seven school districts (herein called joint district) formed a municipal authority, known as the Northampton Area Joint School Authority (herein called Authority). This Authority, acting in compliance with the Municipal Authorities *567Act of 1945,1 duly advertised for bids for the construction of a new high school. After the bids were received, opened and considered, on January 28, 1958 contracts in connection with the proposed high school construction were awarded as follows: Luria Engineering Co. (herein called Luria) the general contract; John F. Miles (herein called Miles) the heating contract; George F. DeLallo (herein called DeLallo) the plumbing contract; William A. Donmoyer Co. (herein called Donmoyer) the electrical contract. Luria, Miles and DeLallo were so-called “union contractors” in that they employed only union labor, while Donmoyer was a so-called “non-union contractor” in that he employed no union labor.2
The work of construction began on or about March 15, 1958 and from that time until August 25, 1958 the general contractor, the plumbing contractor and the heating contractor were all working on the project. Donmoyer did not begin his work until August 25, 1958 and his employees worked on the' project from August 25 to August 29, inclusive, 1958. On September 2, 1958, Local 375 of the International Brotherhood of Electrical Workers (herein called Union) and the Buildings & Construction Trades Council of Allentown, Bethlehem and Easton,3 (herein called Trades *568Council) began picketing the construction site, with sometimes one and at other times two pickets.4 The result was that the employees of Luria, DeLallo and Miles — all members of unions but not of the Union herein involved — refused to cross the picket lines and the work of construction of this high school ceased.
After the construction work had been at a standstill for approximately two months, the seven school districts, the joint district and the Authority, together with Donmoyer, filed a complaint in equity against the Union, the Trades Council, Harry B. Parks (the Union’s Business Agent and President of the Trades Council) and one Louis Greenberg, the only identified picket. A preliminary injunction was sought and the court below granted a rule to show cause why a preliminary injunction should not issue, said rule being made returnable before Judge C. B. Palmer.
The defendants filed both an answer and preliminary objections to the complaint.
A hearing was held at which the plaintiffs presented evidence but the defendants, although they had full opportunity to do so, presented no evidence. After this preliminary hearing, the court below dismissed defendants’ preliminary objections and, preliminarily, enjoined and restrained all four defendants “from doing any act calculated or intended to compel [Donmoyer] to require its employees to become members of either [the Union] or [the Trades Council] by picketing the school building site . . ., or, in furtherance of such purpose, conspiring, combining, agreeing, or arranging with any person or persons, with each other, with any organizations, associations, or trade unions to induce, coerce or intimidate any person or persons who have in the past or who are presently working on the *569[school] project from working on said project or from entering the premises thereof, or, in furtherance of said purpose, interfering with the construction of said school building by [Luria], [DeLallo], [Miles], [Donmoyer], or any of their sub-contractors.”
The court below found, inter alia: (1) on December 18, 1957, after the receipt of sealed bids but before the award of any contracts, one Mr. Toman (an agent for a union not herein involved and vice-president of District 2, Pennsylvania State Building Trades) appeared at a meeting of the Authority, and stated that he represented the trade unions, that he hoped the contract would be awarded to union contractors, and either stated or intimated that “there might be trouble if the union wasn’t satisfied”; (2) in the middle of February, 1958, after the contracts had been awarded, two representatives of Luria attended a conference in the Trades Council office in Allentown, at which Parks and Toman were present and Parks then stated that there would possibly be trouble if the electrical workers went to work and that there would probably be a picket line; (3) that there exists no strike, lockout or labor dispute between the Authority, the joint district, Luria, DeLallo, Miles, Donmoyer and their respective employees; (4) since January 28, 1958 to the time of hearing none of Donmoyer’s employees were invited or asked to join any union; (5) that the purpose of the picketing was to coerce Donmoyer “to ■become union-shop in order thereby to compel its employees to join [the Union] or lose their jobs”; (6) that approximately 2,000 school children in the district were presently affected by the overcrowded conditions therein; (7) at the time of hearing damages to the school building (approximately 18% completed) as the result of the work stoppage amounted to $3,000 to $5,000 with possible other extensive damages to fol*570low; (8) that the controversy was not a labor dispute under the Labor Anti-Injunction Act.
If the purpose of the picketing was the coercion of the employer Donmoyer into the formation of a union shop, such purpose was unlawful and the picketing was properly enjoined: Anchorage, Inc. v. Local 301, A. F. of L., 383 Pa. 547, 119 A. 2d 199. To demonstrate that the purpose of the picketing was coercive it is not necessary for the record to disclose a direct demand by the Union upon the employer for a union shop. The purpose of picketing may be shown either expressly or by implication; to hold otherwise would constitute a failure to face the realities of the present factual picture. See: Anchorage, Inc. v. Local 301, A. F. of L., 383 Pa. 547, supra; Baderak v. Building and Construction Trades Council, 380 Pa. 477, 112 A. 2d 170.
The Union and the Trades Council, even without directly contacting the employer, made it abundantly clear, as found by the court below, that a picket line with the direct result of preventing the employees of the other contractors from crossing the picket line and continuing their work, would be utilized if a single non-union contractor was hired. Although appellants urge that the purpose of the picketing was not coercive, but organizational, not a single one of the three employees of Donmoyer during the entire period was ever personally approached, contacted, or requested, either directly or indirectly, by the Union or the Trades Council to join any union. The known effect of the picket line combined with veiled, but nevertheless real, threats of its utilization on the premises of the school district, without even a token attempt on the part of the Union to personally contact or approach the employees it was purportedly seeking to organize, convincingly and clearly reveals that the purpose of the instant picketing was to coerce the employer Don*571moyer into the formation of a union shop, a purpose which our prior decisions declare unlawful and as constituting conduct which is properly enjoinable.
We have long and strictly adhered to the rule clearly set forth in Lindenfelser v. Lindenfelser, 385 Pa. 342, 343, 123 A. 2d 626: “Our uniform rule is that, on an appeal from a decree which refuses, grants or continues a preliminary injunction, we will look only to see if there were any apparently reasonable grounds for the action of the court below, and we will not further consider the merits of the case or pass upon the reasons for or against such action, unless it is plain that no such grounds existed or that the rules of law relied on are palpably wrong or clearly inapplicable : . . .” See also: Philadelphia v. Philadelphia Transportation Co., 386 Pa. 231, 236, 126 A. 2d 132, and cases therein cited; Riverside Borough School District v. International Brotherhood of Electrical Workers, Local 607, 389 Pa. 637, 638, 133 A. 2d 554; Williams v. Bridy, 391 Pa. 1, 3, 136 A. 2d 832; Parker v. Philadelphia, 391 Pa. 242, 247, 137 A. 2d 343; Penna. Turnpike Commission v. Evans, 392 Pa. 110, 116, 139 A. 2d 530; Summit Township v. Fennell, 392 Pa. 313, 314, 140 A. 2d 789; Herman v. Dixon, 393 Pa. 33, 36, 141 A. 2d 576; McDonald v. Noga, 393 Pa. 309, 311, 141 A. 2d 842.
Acting within the scope of such appellate review, we have examined the record and find that the record discloses reasonable grounds for the action of the court below. The rules of law relied upon by the court below in support of its action are neither palpably wrong nor clearly inapplicable as the opinion of Judge Palmer in the court below readily reveals.5
*572In affirming the order of the court below, we are not unmindful of two recent United States Supreme Court decisions which could conceivably prohibit this Court and the court below from exercising any jurisdiction in the instant proceedings. See: San Diego Building Trades Council, Millmen’s Union, Local 2020, Building Material and Dump Drivers, Local 36 v. Garmon, 359 U. S. 236; Plumbers, Steamfitters, Refrigeration, Petroleum Fitters and Apprentices of Local 298, A. F. of L. v. County of Door, 359 U. S. 354. The impetus of these decisions is felt, however, only where the effect on interstate commerce is sufficient to confer jurisdiction on the National Labor Relations Board. As this Court stated in Haefele v. Davis, 373 Pa. 34, 41-42, 95 A. 2d 195: “The question of federal jurisdiction in labor disputes arises only when employer is engaged in interstate commerce or when his business substantially affects interstate commerce: [citing cases]. The record in this case, as compiled in the court below, does not clearly disclose the extent or even the existence of interstate commerce engaged in or affected by the operation of Vulcan Iron Works. In order to oust this Court of jurisdiction . . . appellants had the burden of establishing facts which would show the interstate character of the business involved.” Evidence of the National Labor Relations Board’s jurisdiction must be either readily ascertainable from the complaint itself or affirmatively proven by the defendant. See: Fountain Hill Underwear Mills v. A. C. W. U. of A., 393 Pa. 385, 143 A. 2d 354; Elisco v. Rockwell Manufacturing Company, 387 Pa. 274, 128 A. 2d 32. The record in the present case discloses no such evidence.
Order affirmed. Costs to abide the event.
Mr. Justice Musmanno dissents.Act of May 2, 1945, P. L. 382, §10, 53 PS §312, which reads in part: “All construction ... of any nature made by any Authority, where the entire cost, value or amount of such construction . . . shall exceed five hundred dollars ($500.00) [with certain exceptions not herein pertinent] shall be done only under contract or contracts to be entered into by the Authority with the lowest responsible bidder, upon proper terms, after due public notice has been given, asking for competitive bids . . .”
On this job Luria had forty men, Miles had three men, De-Lallo had five men and Donmoyer had three men.
An unincorporated labor union composed of representatives and delegates of a number of local trade unions, including the Union.
There is no allegation that the picketing was other than peaceful.
See: West Penn Township School District v. International Brotherhood of Electrical Workers, Local Union 636, 396 Pa. 408, 145 A. 2d 258.