Tired of doing water colors of Dutch cows recumbent upon flat fields, Queen Wilhelmina of The Netherlands spent last week in Switzerland doing water colors of upstanding cows browsing against a background of jagged peaks. While Her Majesty thus rusticated, in preparation for her Jubilee in September, it was confirmed at The Hague that Crown Princess Juliana is expecting a second child. Netherlanders, disappointed that the first was a girl, busied themselves at once last week with prayers that next February they will have a male heir. The Crown Princess, whose gadabout Prince Consort Bernhard last spring took a three weeks' bachelor vacation, leaving her at The Hague, told friends last week: "Benno and I will soon go for a cruise in the Baltic on the yacht we were given as a wedding present.''