The Krupp interests have played a leading role in the war, not only by manufacturing billions of shells and cannon, and by financing propaganda in the United States, but by building submarines. At the Krupp wharves at Kiel some of the best undersea craft are launched. Other shipyards at Bremen, Hamburg and Danzig have been mobilised for this work, too. Just a few weeks before diplomatic relations were broken a group of American doctors, who were investigating prison camp conditions, went to Danzig. Here they learned that the twelve wharves there were building between 45 and 50 submarines annually. These were the smaller type for use in the English Channel. At Hamburg the Hamburg-American Line wharves were mobilised for submarine construction also. At the time diplomatic relations were severed observers in Germany estimated that 250 submarines were being launched annually and that preparations were being made greatly to increase this number.

Submarine warfare is a very exact and difficult science. Besides the skilled captain, competent first officers, wireless operators and artillerymen, engineers are needed. Each man, too, must be a "seadog." Some of the smaller submarines toss like tubs when they reach the ocean and only toughened seamen can stand the "wear and tear." Hence the weeks and months which are necessary to put the men in order before they leave home for their first excursion in sea murder.

But Germany has learned a great deal during two years of hit-and-miss submarine campaigns. When von Tirpitz began, in 1915, he ordered his men to work off the coasts of England. Then so many submarines were lost it became a dangerous and expensive military operation. The Allies began to use great steel nets, both as traps and as protection to warships. The German navy learned this within a very short time, and the military engineers were ordered to perfect a torpedo which would go through a steel net. The first invention was a torpedo with knives on the nose. When the nose hit the net there was a minor explosion. The knives were sent through the net, permitting the torpedo to continue on its way. Then the Allies doubled the nets, and two sets of knives were attached to the German torpedoes. But gradually the Allies employed nets as traps. These were anchored or dragged by fishing boats. Some submarines have gotten inside, been juggled around, but have escaped. More, perhaps, have been lost this way.

Then, when merchant ships began to carry armament, the periscopes were shot away, so the navy invented a so-called "finger-periscope," a thin rod pipe with a mirror at one end. This rod could he shoved out from the top of the submarine and used for observation purposes in case the big periscope was destroyed. From time to time there were other inventions. As the submarine fleet grew the means of communicating with each other while submerged at sea were perfected. Copper plates were fastened fore and aft on the outside of submarines, and it was made possible for wireless messages to be sent through the water at a distance of fifty miles.

A submarine cannot aim at a ship without some object as a sight. So one submarine often acted as a "sight" for the submarine firing the torpedo. Submarines, which at first were unarmed, were later fitted with armour plate and cannon were mounted on deck. The biggest submarines now carry 6-inch guns.

Like all methods of ruthless warfare the submarine campaign can be and will be for a time successful. Germany's submarine warfare today is much more successful than the average person realises. By December, 1916, for instance, the submarines were sinking a half million tons of ships a month. In January, 1917, over 600,000 tons were destroyed. On February nearly 800,000 tons were lost. The destruction of ships means a corresponding destruction of cargoes, of many hundreds of thousands of tons. When Germany decided the latter part of January to begin a ruthless campaign German authorities calculated they could sink an average of 600,000 tons per month and that in nine months nearly 6,000,000 tons of shipping could be sent to the bottom of the ocean,--then the Allies would be robbed of the millions of tons of goods which these ships could carry.

In any military campaign one of the biggest problems is the transportation of troops and supplies. Germany during this war has had to depend upon her railroads; the Allies have depended upon ships. Germany looked at her own military situation and saw that if the Allies could destroy as many railroad cars as Germany expected to sink ships, Germany would be broken up and unable to continue the war. Germany believed ships were to the Allies what railroad carriages are to Germany.

The General Staff looked at the situation from other angles. During the winter there was a tremendous coal shortage in France and Italy. There had been coal riots in Paris and Rome. The Italian Government was so in need of coal that it had to confiscate even private supplies. The Grand Hotel in Rome, for instance, had to give up 300 tons which it had in its coal bins. In 1915 France had been importing 2,000,000 tons of coal a month across the Channel from England. Because of the ordinary loss of tonnage the French coal imports dropped 400,000 tons per month. Germany calculated that if she could decrease England's coal exports 400,000 tons a month by an ordinary submarine campaign that she could double it by a ruthless campaign.

Germany was looking forward to the Allied offensive which was expected this Spring. Germany knew that the Allies would need troops and ammunition. She knew that to manufacture ammunition and war supplies coal was needed. Germany calculated that if the coal importations to France could be cut down a million tons a month France would not be able to manufacture the necessary ammunition for an offensive lasting several months.

Germany knew that England and France were importing thousands of tons of war supplies and food from the United States. Judging from the German newspapers which I read at this time every one in Germany had the impression that the food situation in England and France was almost as bad as in Germany. Even Ambassador Gerard had somewhat the same impression. When he left Germany for Switzerland on his way to Spain, he took two cases of eggs which he had purchased in Denmark. One night at a reception in Berne, one of the American women in the Gerard party asked the French Ambassador whether France really had enough food! If the Americans coming from Germany had the impression that the Allies were sorely in need of supplies one can see how general the impression must have been throughout Germany.