138 



• KNO\A/'LEDGE ♦ 



[Aug. 15, 1884. 



that for the most part we are not sensible of it, and we 

 believe we act by other principles." 



"You are moralising," said she, "to a question of 

 natural philosophy : But 'tis enough for the first time ; let 

 us now go home, and meet here again to-morrow, you with 

 your systems, and I with my ignorance." 



In returning to the Castle, that I might say all I could 

 on the subject, I told her of a third system, invented 

 by Tycho Brahe, who had fixed the earth in the centre 

 of the world, turned the sun round the earth, and 

 the rest of the planets round the sun ; for s-ince the 

 new discoveries, there was no way left to have the 

 planets turn round the earth. But the Marchioness, 

 who had a quick apprehension, said, she thought it was 

 too aflected, among so many great bodies, to exempt the 

 earth only from turning round the sun ; that it was im- 

 proper to make the sun turn round the earth, when all the 

 planets turn round the sun : and tbat tho' this system was 

 to prove the immobility of the earth, yet she thought it 

 very improbable. So we resolv'd to stick to Copernicu!;, 

 whose opinion we thought roost uniform, probable, and 

 diverting. In short, the simplicity of his system convinces 

 us, and the boldness of it surprises with pleasure. 

 (To be contimied.) 



REMAEKABLE STOEMS IN BELGIUM. 



A NUMBER of very remarkable storms occurred in 

 Belgium in July, 1884, and the following account is 

 taken from reports made to the Observatory at Brussels. 

 On the 4th, at Lamorteau, near Virton, from 2h. 34m. to 

 5h. 22m. p.m., ttere was a storm wind, and during eighteen 

 minutes a great fall of hail, making the fields look as if 

 thickly covered with snow. The hailstones were at first the 

 .size of nuts, and then of large peas. At Thirimont, near 

 Beaumont, on the 5th, the hail was the largest ever known 

 there. The stones had sharp angles, and did great damage 

 to crops. The storm did not extend beyond a radius of 

 1,500 metres. On the 13th, at Bruges, during a severe 

 storm, the sky looked as if instead of clouds there were 

 vast eddies of smoke from a huge fire, reflecting flames. 

 The movements of the lower clouds increased in rapidity, 

 the wind rose to a hurricane, and snapped great branches off 

 the trees. Transparent hailstones fell for five or six minutes, 

 the size of small nuts. At Maldegem, east of Bruges, 

 almost at the same time, there was a deluge of rain mingled 

 with pieces of ice from 25 to 40 millimetres in diameter 

 (1 inch to li). They were round, lenticular, and angular, 

 striking the ground with extraordinary force. A water- 

 spout passed within 3,000 mfetres, destroying hundreds of 

 trees. At Ostend, on the same day, some hailstones were 

 as big as j)igeons' eggs and some as big as fowls' eggs. One 

 of these, when cut in the direction of its longest diameter, 

 exhibited a nucleus, surrounded with successive layers, 

 alternately transparent and opaque. The surface was very 

 irregular, with clear protuberances. At Haesrode, near 

 Louvain, at 2.30, on the 13th, a small white cloud appeared 

 and suddenly discharged hailstones as big as eggs, one 

 weighing over 8 oz. They varied in shape — oval, hemi- 

 spherical, triangular, and some spinous, like a prickly pear. 

 This storm only lasted three or four minutes, and only ex- 

 tended over the small space of from half a metre to a 

 mfetre ! At Hechtil (Limbourg), on the same date, hail- 

 stones fell over 3 inches in diameter. 



During the storm of July 13, Baron van Ertborn, at 

 Aartselear, near Antwerp, examined with a telescope a 

 large cloud 50 deg. above the horizon, and saw that it was 



formed of seven superposed layers, the lower ones eddying 

 and moving quickest. Curved flashes of lightning darted 

 from one layer to another. On July 17, near Arlon, pieces 

 of ice fell 3 to 31 inches in diameter, breaking glass, kill- 

 ing poultry, and cutting fruit-trees. Storms of this kind 

 are said to be very rare in Belgium. S. 



THE 



INTEENATIOXAL 

 EXHIBITION. 



HEALTH 



XII.— WATER AXD WATER-SUPPLIES— (conHnued). 



THE description of Mr. Roberts's " Rain -Water 

 Separator," given in our last communication, is an 

 apt introduction to the subject of water-purifying appli- 

 ances, which we now propose to deal with. In the " East 

 Central Gallery B," may be seen, in active operation, all 

 the forms of apparatus that are of any value in the present 

 enlightened day, when Darwin's great law of the "survival 

 of the fittest " holds its sway more powerfully than ever. 

 The plan we have chosen to adopt in our remarks upon the 

 inventions here displayed, is to place before our readers a 

 descriptive account of the fyjies that have been resorted to 

 in gaining certain desired ends, rather than a serial dis- 

 course upon the relative merits of the various patents. In 

 illustration of these principles, we shall select the most 

 suitable examples at our dbposal, so that our series of 

 reviews shall embodj^ a digest of the highest possible value 

 for those who wish to exercise their own discretion in the 

 choice of what we deem to be one of the most essential 

 requisites in every household — a good filter. 



Type I. — As a natural sequence of the rain-water sepa^ 

 rator, which is adapted to procure a supply of good soft 

 water suitable for all domestic purposes, save drinking,* 

 we would draw attention here to " Stall 420," and the 

 " Grant Revolving Ball Water Filter," the value of which 

 lies in the fact that a tolerably pure water, such as that 

 derived from a Roberts Separator, or delivered to town 

 and suburban dwellings by water companies, may be 

 rendered fit for drinking in an incredibly short space of 

 time. It is, without doubt, the best rapid water filter for 

 the above-mentioned sources of supply ; it can be fastened 

 on to any existing water-pipe with the utmost ease ; may 

 be as readily cleansed and re-charged with the filtering 

 medium ; and, when " turned on full," there is but a slight, 

 almost inappreciable, diminution in the rapidity of flow 

 from the tap. We can safely recommend this filter to the 

 notice of those who desire to have an unlimited supply of 

 good, pure water always readily available, more especially 

 in the kitchen ; and to convince our readers of its practical 

 utility, we cannot do better than give an outline of its 

 general anatomy. So far as we are aware, this type of 

 filter stands alone — it has not yet been copied ; in one par- 

 ticular, however, it may be placed amongst the so-called 

 high-pressure filters. 



The " Grant Revolving Ball Water Filter " consists of a 

 spherical metallic case, the smallest manufactured size of 

 which, for domestic purposes, is about 2 inches in diameter, 

 and under pressure from the tap diminishes the ordinary 

 rate of delivery by about only 20 per cent. Within the 

 case there is a hollow metal ball, designed to hold the 

 filtering medium (granular animal charcoal), and every 

 drop of water which passes into the mechanism is forced 



* In making this proviso, we desire it to be understood that, in 

 most cases, the rain-water obtained through the tise of the Roberts 

 " Separator," may be also used for drinking ; but it is well to pnrifj- 

 it still further by efficient filtration, so as to render the result 

 doubly secure. 



