SCIENTIFIC NEVS^S. 



[Nov. 1st, iS 



GENERAL NOTES. 



Preservation of Fruit. — Professor Tyndall has proved 

 that atmospheric germs cannot pass through a layer of cot- 

 ton, and it is now said that preserved fruit may be kept in 

 perfect condition by covering the jar with cotton batting. 

 Putrefaction is caused by minute atmospheric germs. 

 These are expelled by cooking, and the cotton batting pre- 

 vents their return when the fruit cools. 



New Alu.minium Works. — An experimental trial is being 

 made at Tyldesley, by a London syndicate, of Dr. Kleiner's 

 process for the reduction of aluminium by electricity. Plant 

 of sui^cient capacity to give the process a fair trial is being 

 put down, and has been principally supplied by Messrs. 

 Mather and Piatt, of Salford. It is intended to carry on 

 operations for at least twelve months, and, in the event of 

 successful results being obtained, to put down large works 

 and plant. 



Submarine Earth Cooling. — M. Faye, the French 

 astronomer, has drawn attention at a recent meeting of the 

 Paris Academy ot Sciences to the apparent geological law 

 that the cooling of the terrestrial crust goes on more rapidly 

 under the sea than with a land surface. Hence, he argues 

 that the crust must thicken under oceans at a more rapid 

 rate, and so gives rise to a swelling-up and distortion of the 

 thinner portions of the crust, in other words, to the forma- 

 tion of mountain chains. 



Cloud Thickness and Rain. — In a communication to the 

 London Meteorological Society Captain Toynbee states as 

 his conclusion that clouds of not less than 2,000 feet in 

 thickness are seldom accompanied by rain, or if they are 

 it is very gentle, consisting of minute drops ; with thickness 

 of between 3,000 and 4,000 feet the size of the drops is 

 moderate ; with increasing thickness of the clouds comes an 

 increasing size of the drops, and at the same time the 

 degree of temperature becomes lowered. When the thick- 

 ness amounts to more than 6,000 feet hail is produced. 



New Dry Plate Competition. — Those who have a turn 

 for experimental work may note that M. Davanne offers a 

 prize of ;^40 {i.e. 1,000 francs) for a new kind of dry plate, 

 which shall combine the advantages possessed by collodion 

 and gelatine films respectively. Great rapidity, ease of 

 manipulation, and simphcity are the three main qualities 

 which the competitors must keep in view. All applications 

 must be sent to Paris before the last day of this year, and 

 must be accompanied by a detailed description of the method 

 of working, together with negatives taken by the process, 

 and prints from the same. — Camera. 



The Measurement or Lightning. — The length of a flash 

 of lightning is generally under-estimated. The longest 

 known was measured by M. P. Petit, of Toulouse. This 

 flash was ten and a half miles in length. The longest 

 interval ever remarked between the flash and the report 

 was seventy-two seconds, which would correspond with a 

 distance of fourteen miles. Direct researches have shown 

 that a storm is seldom heard at a greater distance than 

 seven to ten miles, while the average are barely heard over 

 four or five miles off. This fact is more curious, as cannon 

 may be distinctly heard double or treble that distance, and 

 in equal cases much better. 



The Photogravure Controversy. — Annan and Swan 

 replied in the Atheneum to Professor Herkomer's strictures 

 upon photogravure. They contend that photogravure is not 



the purely mechanical and chemical process which it has 

 been supposed to be, and that it has already done engravers 

 and their art a great deal of good. Messrs. Annan score a 

 point when they say it would have been impossible to have 

 got an engraver for Sir Noel Paton's picture of Oberlin and 

 Titania (reproduced by them in photogravure), on account 

 of the number of figures in it ; and Sir Noel himself said 

 that photogravure was the only method by which it could 

 be adequately rendered. — Photographic News. 



Reassuring. — A contemporary remarks that scientists, 

 as the result of certain plausible and ingenious experiments, 

 have come to the conclusion that the people of London 

 drink polluted water, inhale polluted air, and that their 

 chances of existence are reduced to a minimum. Yet in 

 spite of these depressing speculations, Londoners, instead 

 of meekly affirming scientific truths by dying oft-hand, ob- 

 stinately persist in living and enjoying themselves in their 

 own fashion. Indeed, such is their contrariness that, de- 

 spite the billions of bacteria in the water they drink and 

 the micro-organisms in the atmosphere they breathe, London 

 is, on the whole, the healthiest large city in the world. 



A Steam Balloon. — There is much talk of a steam 

 balloon which is being built by a M. Yon. The form is that 

 of a fish, and its dimensions are gigantic, the length being 

 200 ft. It is to be enclosed in the usual manner in a net, 

 from which the car will be suspended. The latter will be 

 provided with a rudder and a trapezoidal screw, to be 

 driven by a compact steam engine, weighing 3,7401b. This 

 weight allows 7olb. per i h.p. M. Yon, in an account which 

 he has published of his invention, says that he hopes to 

 attain a speed, in a calm atmosphere, of thirteen or fourteen 

 miles a second. Such a speed would not disgrace one of 

 the inferior members of the planetary system, but, possibly, 

 M. Yon means hours when he talks of seconds. 



Scientific Enterprise in America. — The zeal with which 

 the sciences of astronomy and meteorology are pursued in 

 America, and the ingenuity displayed in applying to the 

 purposes of ordinary life the results of the study of those and 

 kindred subjects is striking. As an example, we may men- 

 tion that, it having been decided by the Signal Service of 

 the United States to abandon a number of the stations on 

 the Pacific Coast, the proprietor of the San Francisco 

 Chronicle oft'ered to maintain and conduct those stations at 

 his own expense, on condition that the Government would 

 allow the instruments to remain. The ofter has been 

 accepted, and henceforth the San Francisco Chronicle will 

 provide observers, and pay for telegrams and warnings. 



Steam Tricycle. — A recent number of La Nature has an 

 illustrated account of a steam tricycle contrived by MM. Roger 

 de Montais and L'Hcritier, which vi'ill go 16 to 18 kilometres 

 an hour with one person and 14 to 16 with two. In front is a 

 small boiler heated by petroleum, which gives ofi", it is said, 

 no smoke nor smell, nor unpleasant heat. Under the seat is 

 the petroleum reservoir, holding ten litres, enough to last 

 ten hours, and behind is a water reservoir which holds 

 thirty-four litres, allowing a two and a half hours' run 

 without fresh supply. This water reservoir has one com- 

 partment for cold water, and another for water constantly 

 heated by escape of steam ; the latter feeding the vertical 

 engine behind, and the former having steam turned into it 

 at will. 



The Great Bell of Cologne. — An official notice has 

 been published of the great bell for the Cathedral of 



