Abstract: A connecting arrangement for connecting two elements with one another, particularly a mast and a boat body of a wind surfboard comprises a male member connected with one of the elements, and a female member engageable with the male member with snap action and connected to another of the elements. At least one of the members connected with a respective one of the elements is rotatable within the horizontal plane. Preferably, this one member is rotatable within the range of 360.degree.. The male member and the female member together form a spherical joint. The male member may include a bolt section and a sperical section connected therewith whereas the female member may include a bolt portion and a cup portion connection therewith and adapted to receive the spherical section of the male member therein.

Abstract: Substantially pure, synthetic crystalline .beta.-wollastonite having a specific BET surface of 1-30 m.sup.2 /g made by first producing calcium silicate hydrates having a molar ratio of SiO.sub.2 :CaO = about 0.7 to about 1.3 by hydrothermal treatment of an aqueous mixture of a source of CaO and SiO.sub.2 and then annealing the calcium silicate hydrates at about 800.degree.C to about 1150.degree.C to convert them to the .beta.-wollastonite. The invention also encompasses the use of the calcium silicate hydrates and the .beta.-wollastonite in the manufacture of ceramic materials and glazings.