War is horrible. It is a crime against humanity and utterly ineffective in resolving any kinds of disputes. But we can't deny that armed conflicts also gave us brilliant inventions. The patent records of the United States, England, and Germany indicate that war is a powerful stimulus to invention. One of the most famous examples is the sun lamp. In the winter of 1918, half of all children in Berlin were suffering from rickets—a condition whereby bones become soft and deformed. At the time, the exact cause was not known, although it was associated with poverty. Doctor Kurt Huldschinsky decided to conduct an experiment on his patients. He put them under mercury-quartz lamps which emitted ultraviolet light. As the treatment continued, the bones of his patients were getting stronger. In May 1919, when the sun of summer arrived, he had them sit on the terrace in the sun. The results of his experiment, when published, were greeted with great enthusiasm. Children around Germany were brought before the lights. In Dresden, the child welfare services had the city's street lights dismantled and taken to hospitals to be used for treating children. Researchers later found that Vitamin D is necessary to build up the bones with calcium and the production of Vitamin D is triggered by ultraviolet light. The undernourishment brought on by WWI produced the knowledge to cure the ailment. Another invention that also owed its success to WWI is Daylight Saving Time (DST). The idea of putting the clocks one hour forward in spring and back in autumn was not new when WWI broke out. Benjamin Franklin had suggested it in a letter to The Journal of Paris in 1784. Candles were wasted in the evenings of summer because the sun set before human beings went to bed and sunshine was wasted at the beginning of the day because the sun rose while they still slept. Similar proposals were made in New Zealand in 1895 and in the UK in 1909, but without concrete results. It was WWI that secured the change. Faced with acute shortages of coal, the German authorities announced that from April 30, 1916, the clocks should move forward from 23:00 to midnight to give an extra hour of daylight in the evenings. What started in Germany as a means to save fuels quickly spread to other countries. Britain began three weeks later on May 21, 1916. Other European countries followed. On March 19, 1918, the US Congress established several time zones and made DST official from March 31. After the war ended on November 11, 1918, DST was abandoned, but the idea had been planted and it eventually returned.