The next year Watts was appointed vice and deputy consul-general at Cairo, Egypt, where he was in charge during the Spanish–American War. While there he was instrumental in preventing the Spanish fleet, under Admiral Camara, from coaling at Port Said, before hurrying through the Suez Canal to attack Admiral Dewey's fleet at Manila Bay. Watts dissuaded Evelyn Baring, 1st Earl of Cromer, the British counsel-general in Egypt, from permitting Camara to access coal owned by Spain, while at the same time acquiring a lien over coal available in Suez from other sources. The Spanish fleet's inability to obtain coal in Egypt resulted in the fleet being ordered back to Spain. Before leaving this post, he was decorated by the Khedive with the Order of Osmanieh. During the next two years he was consul-general at Kingston, Jamaica, and from there went to Prague, Bohemia.
Russo-Japanese war
While at Prague he accepted the position of consul-general at St. Petersburg, which was then the capital of the Russian Empire and its largest city. He served there from 1903 to 1907, a turbulent period that included the Russo-Japanese War and the Revolution of 1905. In recognition of his services in protecting Japanese interests in Russia during that war, he was decorated by the Emperor of Japan with the Order of the Rising Sun and with that of the Sacred Treasure.
World War I
From April 1907 to April 1917, he was consul-general at Brussels, Belgium. World War I raged during the last two and one-half years of that period, when the German Empire occupied Brussels and much of Belgium. Both before and after the German occupation, Mr. Watts was instrumental in protecting the interests of American citizens, as well as representing and caring for British and Japanese interests and those of other belligerents. When the United States entered the war in 1917 all consular offices in German-occupied Belgium were discontinued, and Mr. Watts was ordered home. He was acting consul at Halifax, Nova Scotia, on December 6, 1917, when the, a vessel loaded with munitions, exploded in the harbor, razing a large section of the city. The U.S. consular offices, located within three blocks of the waterfront, were wrecked, but Watts managed to survive because, at the time of the explosion, he was late for work.
Personal life
In 1871, Watts wed Emily Pepper, daughter of Dr. William Pepper, Sr. and sister of Dr. William Pepper, Jr. of Philadelphia. They had four children:
Ethel Constance Watts, who married Francis Chambers Harris in 1895. After his death in 1904, she married Victor Clark Mellen, a son of William Proctor Mellen, in 1906.
Marian Watts
Henry Miller Watts, who married Laura Barney, a daughter of Charles D. Barney and granddaughter of financier Jay Cooke.
In May, 1918, he was appointed consul-general at Hamilton, Bermuda. His health began to fail while at this post. He died July 13, 1919, in Philadelphia.