Mrs. Sidney Webb, who has lately returned from a two months' visit to Russia., extending from the Gulf of Finland to the Sea of Azov, will describe the economic and constitutional basis of what may be regarded as a new type of civilization. Mrs. Webb stayed on the gigantic State farms, and went for a cure to a celebrated Caucasian Spa, now given up to 'rest houses' for trade unionists. She will deal in her talk tonight with the novel constitution of the U.S.S.R., its four blocks of mass organization, its exclusive membership, fanatical faith, stern discipline, and elaborate code of conduct, that makes it half political party, half religious order. She will explain, too, the Leninist League of Communist Youth, with its millions of members and its double aim of self-discipline and self-improvement, and personal initiative in the service of the community; concluding with a statement of the economic theory of the General Plan and the difficulties in the way of its fulfilment.