Frothingham gives us to understand that they were displayed on liberty-poles and on the famous "Liberty Tree" on Boston Common. In this connection, we will quote a few lines from a letter, dated Philadelphia, December 27, 1775, to show the temper of the public mind at that time, and to indicate the name given to the colonies, whose flag we are now about to consider. "TO THE PEOPLE OF NORTH AMERICA: "PHILADELPHIA, December 27, 1775. "Those who have the general welfare of the United English Colonies in North America sincerely at heart, who wish to see peace restored, and her liberties established on a solid foundation, may, at present, be divided into two classes, viz.: those who 'look forward to an independency as the only state in which they can perceive any security for our liberties and privileges,' and those who 'think it not impossible that Britain and America may yet be united.' "If the present struggle should end in the total independence of America, which is not impossible, every one will acknowledge the necessity of framing what may be called the 'Constitution of the United English Colonies.' If, on the other hand, it should terminate in a reunion with Great Britain, there yet appears so evident a necessity of such a constitution that every good man must desire it."[42] [42] American Archives, 4th series, vol. iv. p. 467. This letter shows the importance the Union of the Colonies, lately entered into, held in the mind of the public. Prior to its being entered into, its necessity was thus forcibly indicated to the public mind. The newspapers commonly bore the device of a disjointed snake, represented as divided into thirteen portions. Each portion bearing the initials of one of the colonies, and under it the motto, "Join, or die." Thus impressed, we can readily perceive how naturally they seized upon the flag in use in the mother country and its dominions, as an emblem of union among the members of that mother country, to indicate the necessity of it among the colonies, and, by displaying it from liberty-poles, &c., indicated the object for which union was necessary, viz.: to secure the liberty of British subjects. The first authentic account of the display of the Union flag, as the flag of the united colonies, is from the pen of General Washington, in a letter addressed to Colonel Joseph Reed, his military secretary. "CAMBRIDGE, January 4, 1776.