i8 DESIGN IN NATURE 



" Immanuel Kant, the great German philosopher, was the first to guess the wonderful process that preceded the 

 foundation of solar systems ; but it was reserved for the celebrated French mathematician and astronomer, Laplace, 

 to formulate definitely Kant's now famous nebular hypothesis. This supposed that the sun and all the planets, 

 with their retinues of satellites, originally existed as a huge globe of fiery vapour, which, having acquired a slow 

 rotary motion, gradually assumed the form of a gigantic whirlpool. As time went on, the vast rings of tenuous 



Fk;. 6. — Photograph of the Great Nebula in the eoiistellation of Andi-onieda, by Dr. Isaac Roberts, 

 F.R.S. He rlescribes it as Spiral Xebula M. 31, Andromedfe. The photograph was taken with a 20-inch 

 reflector with an exposure of ninety minutes on October 17, 1895, and covers the region between R. A. Oh. 

 34m. Os. and R. A. Oh. 40m. 41s. The nebula, Dr. Roberts explains, forms a left-handed spiral, and 

 is better seen in the negative than in the photographic print. 



matter so created gradually condensed unevenly here and there, each patch becoming a centre of attraction, drawing 

 more and more material around it, the largest, of course, remaining approximately in the middle. In this way 

 the central mass became the sun, and the smaller condensations resolved themselves into the planets. Visual 

 demonstration of this daring theory was not long delayed. About the middle of last century Lord Rosse, with his 

 huge telescope at Parsonstown in Ireland, discovered the first of the so-called spiral nebulae, and soon afterwards 

 Sir WilUam Huggins announced their gaseous character. Even then, however, their extraordinary nature was not 

 fully realised, and it was only a short time ago that photography, supporting the joint testimony of the telescope 



