The correspondence between Leibniz and Teuber continued. From Hanover, on 3^rd July 1716, Leibniz wrote a letter to Teuber informing him of his visit to Zeitz to clear up the remaining problems connected with his calculator, which was a marvelous invention of the time. His calculator performed flawlessly doing all sorts of mathematical operation. - Addition, subtraction, multiplication, and division. Moreover, his calculator could also extract a root. He told Teuber in the letter that he was going to visit Duke Moritz Wilhelm. According to the court diary, Leibniz arrived on 10^th July 1716 and Duke Moritz Wilhelm treated him as the guest of honour. Leibniz spent a week there, amending his calculator, which had been designed there, and on his way back paid a brief visit to Orffyreus again.

On 3^rd August 1716 Leibniz wrote to Teuber: “I spoke with Mr. Orffyreus, who is about to move to Kassel. He has high hopes that, with the support and authority of His Serene Highness, many eminent princes can be approached and that he will be able to get a just reward. But to achieve this, he should allow the machine to run for as long as two weeks.”

         Leibniz left Zeitz on 17^th July. By that time, he learnt that Orffyreus was moving to Kassel. Leibniz was optimistic that after the construction of the new wheel, Orffyreus would be able to reveal of the secrets of the machine and get his reward, as difficulties would be straightened out with help of Count Karl.  He hoped that he could also contribute in further development of machine. Besides, he would have chance to deal with theoretical aspects of the problem which in turn might help him to build up a new theory on nature of Vis Viva.  Unfortunately, things did not happen as Leibniz expected.  His participation was prevented by his untimely death on 14^th November 1716. He passed away at the age of 70. It was a big personal loss to Orffyreus as he lost further support of Leibniz for his invention.  Leibniz’s authority, knowledge and his obvious interest and support were vital to Orffyreus.  Leibniz’ death put an end to the possibility of recognition of perpetual motion in mainstream natural philosophy.  Leibniz was a respected scientist and perhaps the most acknowledged on the Continent, if he had lived longer, there possibly perpetual motion would have been established in science as a valid thing.  It was a turning point for Orffyreus. Though prospects were bleak, Orffyreus did not lose courage

              During the same period, Landgrave of the Hesse- Cassel [i], Count Karl much interested in science of mechanics, came to know about Orffyreus and his wonderful wheel. Leibnitz also recommended Bessler to Count Karl for the sponsorship of his invention. Count Karl was a rich and royal elite so was able to help Orffyreus’ work substantially. At this time, Count Karl, was 62 years old and was living at Weissenstein Castle at Hesse-Kassel. Though Count Karl ruled over one of the tiny quasi-independent states which were numerous in that of Germany’s development, leading powers in northern Europe well recognized him as a stead fast ally in the many wars which took place at his time.  He had personal and political association with the kings of England, Poland, Prussia, and Sweden He negotiated at high levels on several political issues.  He was a successful ruler.  Conditions of the Hesse-Cassel were poor before he came to power.  His small country became well-off due to his mercenary army which could be hired from him by other states at war - at a considerable price, of course. In England it was the trading of slaves and other colonial produce that proved to be the most profitable of businesses. Count Karl gained his money and respect by equipping and hiring mercenaries.

Count Karl had spent nearly all his life with warfare but in the latter part of his life he turned to the arts and sciences. He understood importance of science and technology to develop industry.  He worked hard, encouraged scientist, patronized them, engaged them in many large building projects which were successful and contributed a lot to the development of the state and as a result, when he had died, he left Hesse -Cassel in an excellent financial position. 

 Count Karl was very popular for his collection of the latest scientific instruments.  Among these were various unusual clocks based on rolling ball mechanism, erroneously called as perpetual mobile.  He purchased one such perpetual mobile from Cassipani, inventors of several unusual clocks during his visit to Italy between December 1699 and April 1700. We can therefore see that the Landgrave had a technical vein. He exhibited numerous machines, devices and other things of technical interest.  Many eminent scientists living in his time acknowledged his merit.  Gottfried Leibniz and Christian Wolf were among his admirers. 

The monarch took an interest in technology throughout his life, in so much as he, a devoted Protestant, had invited Huguenots who were exiled from France to his own country. Among those arriving at court was Denis Papin, who had achieved great merits in the development of the steam engine. The Count Karl patronized Denis Papin, inventor of steam engine.  . Papin had moved to Kassel in 1695, where he carried out a series of famous experiments with the help and support of the Landgrave. He became Professor of Mathematics at the University of Marburg, and remained in the Landgrave’s services for 20 years. Papin had been a collaborator with Huygens in Paris and Boyle in London. He invented the safety valve and an early form of pressure cooker. Papin could not carry out his experiments with the steam engine in the court for very long because Desagulier soon claimed that he invented a better steam engine which really proved to be better than Papin’s. In his castle, Count Carl installed the first steam engine in mainland Europe. It had the simple task of raising water for the cascade at the front of his castle – much to the astonishment of the public.  

·        Count Karl offers Orffyreus a post of councilor ( 1716 )