In 1663, his book entitled _Optica Promota_, which contained a description of his telescope, was published in London, and thither Gregorie went, hoping that by the assistance of a practical workman he might realise his ideal. His book had been much read by mathematicians, and amongst others by John Collins, the Secretary to the Royal Society. We can picture then the mutual pleasure with which these two men met. It was in an alehouse, where possibly the jolly tavern keeper took the Aberdonian through the fumes of his stuffy parlour, and presented him to Master Collins as a likely friend for him; anyway, this was the beginning of a life-long friendship, and Collins, who had realised at once what a possibility lay in the proposed reflecting telescope, determined to have a glass made on the principles which Gregorie had suggested in his book. With this object in view, he took his new Scottish friend to the most skilled glass-grinder in London, but, alas! in vain. Mr Reeves could not overcome the difficulty of obtaining conoidal reflectors, but to the great mathematicians of that day, and it was a day of giants, the discovery was magnificent, and from the hands of astronomy’s master craftsman, the reflecting telescope emerged in 1668 in a more beautiful form, as Newton’s telescope. Before Gregorie’s time, the telescopes in England were many of them immensely long, going up even to three hundred feet, and at this length they were hardly available for scanning the heavens. The new reflector brought the size down to six or nine feet, and the idea was so ingenious, that it made Gregorie famous, and what was more, opened the door for him to friendship with Newton and Collins, to acknowledgment as an original worker by Huygens, and awakened in the Father of the Catholic Church an apprehension that one Gregorie, a Scot and a heretic, might come to deserve the spiritual blight which he is empowered to give in placing a book on the Index! It was not so very long before, that Galileo—an earlier maker of telescopes—had been accused by the learned scribes and pharisees of his day, of magic. ‘Oh, my dear Kepler,’ says Galileo to his brother astronomer in one of his most amusing letters, ‘how I wish that we could have one hearty laugh together! Here at Padua is the principal professor of philosophy, whom I have repeatedly and earnestly requested to look at the moon and planets through my glass, which he pertinaciously refuses to do. Why are you not here? What shouts of laughter we should have at this glorious folly, and to hear the professor of philosophy in Pisa labouring before the Grand Duke with logical arguments, as with magical incantations, to charm the new planets out of the sky!’ It is well that Galileo laughed at this stage of his life; when he fell into the hands of the Inquisition it became no laughing matter, and even after he had renounced his views, he was subjected to many griefs, and to a long incarceration in an Italian prison.