Generation of a hyperbolical cylindroid
                                Date
                            
                            
                                10 June 1669
                            
                            
                        
                            
                            
                            
                                Creator
                            
                            
                                Unknown, Artist
                            
                            
                        
                            
                            
                            
                                Object type
                            
                            
                            
                        
                            
                            
                            
                                Archive reference number
                            
                            
                            
                        
                            
                            
                            
                                Manuscript page number
                            
                            
                                p71
                            
                            
                        
                            
                            
                            
                                Material
                            
                            
                            
                        
                            
                            
                            
                                Dimensions
                            
                            
                                height (page): 360mm
width (page): 230mm
                            
                        
                            
                            
                            width (page): 230mm
                                Subject
                            
                            
                            
                        
                            
                            
                            
                                Description
                            
                            
                                On 10 June 1669, Wren presented to the Royal Society his idea that a machine for grinding hyperbolical lenses could be developed from the principle that the axis of a cylinder was a hyperbolic surface; this was ordered to be registered and was duly entered in the Register Book here. Robert Hooke was asked to make a machine based on Wren's design, but it appears he never made one. Wren hinted at the idea of a machine in Philosophical Transactions vol. 4, no. 48 (June 1669), which was followed by another figure (Cl.P/1/11/001a (previously 11a)) published later that year in Philosophical Transactions vol. 4, no. 53.
                            
                            
                        
                            
                            
                            
                                Object history
                            
                            
                                At the meeting of the Royal Society on 10 June 1669, ‘Dr. Christopher Wren explained the model of his engine for grinding hyperbolical glasses, viz. upon what geometrical principle it depends, and how that is to be applied to practice. The president affirmed, that he had considered the principle, it being formerly imparted to him, and had found it mathematically true; and as to its application to use, the success of that depended on experiment. The contrivance was, that in this engine there was a complication of three different motions, whereby three bodies so work upon another, as to produce an hyperbolical figure; any irregularity, by the encountering of one another, being immediately rectified. Dr. Wren intimated, that great care must be had in setting the engine, that being somewhat nice, since the three axes must all intersect in a point, and one at the right angles with the other two. It was ordered, that the paper containing the demonstrations of this should be registered, and an engine be made by the care of  Mr. Hooke, to try the principle of the matter’ (Birch 2:379).
17 June 1669, ‘Mr. Hooke excused himself for having prepared no experiments for this meeting. He was ordered to take care, that against the next either his own new instrument for working elliptical glasses, or that of Dr. Wren for grinding hyperbolical ones, might be ready’ (Birch 2:383).
C. Wren, 'The generation of an hyperbolical cylindroid demonstration and the application thereof for grinding hyperbolical glasses hinted at', Phil. Trans. vol. 4, no. 48 (June 1669), pp. 961-62, ref. to fig. I, 961-62.
                            
                        
                            
                            
                            17 June 1669, ‘Mr. Hooke excused himself for having prepared no experiments for this meeting. He was ordered to take care, that against the next either his own new instrument for working elliptical glasses, or that of Dr. Wren for grinding hyperbolical ones, might be ready’ (Birch 2:383).
C. Wren, 'The generation of an hyperbolical cylindroid demonstration and the application thereof for grinding hyperbolical glasses hinted at', Phil. Trans. vol. 4, no. 48 (June 1669), pp. 961-62, ref. to fig. I, 961-62.
                                Related fellows
                            
                            
                                Christopher Wren (1632 - 1723, British) , Architect
                            
                            
                        
                            
                            
                            
                                Associated place