7i6 



THE POPULAR SCIENCE MONTHLY. 



portion of the light is wasted. M. Cleman- 

 dot aims by his process to make all the light 

 available for illuiuination. It is based on 

 the principle which governs the diffusion of 

 the light of the sun. This is effected by va- 

 pors floating between us and the sun, which 

 distribute the light equally without stopping 

 more than a very small proportion of it. 

 To imitate these vapors he uses a solid sub- 

 stance, but in a condition so attenuated as 

 to be, for practical purposes, almost the same 

 as vaporous. It is glass, spun into threads 

 one hundred and seventy-five times finer than 

 a hair, or forty-five times finer than the finest 

 silk fiber, with which he surrounds the light 

 with a double envelope. His glass-fleeces 

 are put into a lantern constructed especially 

 for the purpose, so as to exclude dust, the 

 glasses of which may be given any desired 

 degree of opacity, and any color, including 

 those colors which will neutralize the injuri- 

 ous properties of the electric light. The ap- 

 paratus can be adapted to any of the sys- 

 tems of electrical lighting. 



William Lassell. William Lassell, LL. 

 D., F. R. S., the famous astronomer and 

 maker of telescopes, died October 5th, in 

 the eighty-second year of his age. His 

 name is closely associated with the history 

 of the reflecting telescope. About 1820, 

 not having sufficient means to enable him to 

 buy expensive instruments, he began to con- 

 struct reflecting telescopes for himself, be- 

 ginning with a Newtonian and a Gregorian 

 telescope of seven-inch aperture, with which 

 be succeeded so well that he was encouraged 

 to make a Newtonian instrument of nine- 

 inch aperture. In 1844 he began an in- 

 strument of two feet aperture and twenty 

 feet focal length, in the making of which 

 he introduced many improvements over the 

 similar instrument of the Earl of Rosse. 

 With this instrument he discovered the sat- 

 ellite of Neptune in 1846, the eighth satel- 

 lite of Saturn, simultaneously with Profess- 

 or Bond, in the United States, in 1848, and 

 two satellites in addition to the two already 

 known, of Uranus, in 1851. He afterward 

 made an instrument of four-feet aperture 

 and thirty-seven feet focus, which he set up 

 at Malta, and with which he made numerous 

 observations of nebulae and planets, be- 

 sides preparing a catalogue of six hundred 



new nebula3 discovered at Malta. His latest 

 recorded work was the construction of an 

 improved form of machine for polishing 

 large telescopic mirrors, which is described 

 in the " Transactions of the Royal Society " 

 for 1874. 



Climatology of Enrope. The climate 

 of Western Europe is ameliorated by the 

 warmth of the Gulf Stream in winter, and 

 by ihc neighborhood of the ocean in summer, 

 and approaches what is called an insular 

 climate. In Eastern Europe these modify- 

 ing influences cease to be felt, and the cli- 

 mate gradually assumes a continental char- 

 acter, with greater differences of tempera- 

 ture, colder winters and warmer summers. 

 The differences in the summer temperatures 

 of the eastern and western regions are less 

 marked than those in the winter tempera- 

 tures, and amount at most to about 27. 

 For the greater part of the continent the 

 difference in the temperature of July is not 

 more than about 18. The mildest summers 

 are felt in Ireland and Norway, and the hot- 

 test in Southeastern Europe. The differ- 

 ence is perceptible between places in cor- 

 responding latitudes in the southeast and 

 southwest. Thus, Syracuse is 7 and Sebas- 

 topol is 5 j warmer in July than Lisbon and 

 Oporto. A similar difference, but less in 

 extent, appears in going eastward along the 

 northern parallels. The differences in the 

 winter temperatures of the several parts of 

 the continent are much more marked than 

 are those of the summer temperatures. The 

 mildest winters are felt along the Mediter- 

 ranean coast and in the Iberian Peninsula, 

 where the mean temperature in January is 

 from 16 to 19. The next mildest are 

 those of the western coast of France and the 

 southern coast of England and Ireland. The 

 winters of western Scotland and the Orkney 

 and Faroe Islands are milder than those of 

 Berlin and Milan ; those of the Arctic coasts 

 of Scandinavia than those of the Gulf of 

 Bothnia, as is shown by the fact that the 

 Arctic fiords of Norway, even as far as 

 North Cape, are not frozen, while the Gulf 

 of Bothnia is regularly frozen in winter. In 

 Russia the January temperature diminishes 

 as we go east, so that, while it is about 24 

 at Warsaw, it is reduced to 4 at Uralsk. 

 The highest annual mean temperature, the 



