SCIENTIFIC NEWS. 



[Feb. 3, iS 



ment of certain micro-organisms, and to similar agencies must 

 be ascribed such part of the world's vinegar and acetic acid as 

 is not obtained by the destructive distillation of wood, etc. 



By the application of pure " cultivations " of different zymo- 

 genic organisms in special media, I have already obtained 

 evidence that a number of alkaloids, glucosides, and neutral 

 principles, chiefly of a highly toxic character, may be in small 

 quantity produced, and I look forward confidently to that 

 period of the world's history — although probably not within 

 the span of my own life — when our most valuable drugs and 

 medicines will be largely produced in zymogenic facto7-ics 

 constructed expressly for such purposes. 



The constitutions which must necessarily govern the initial 

 designs for, and the subsequent working of, factories of this 

 kind, are doubtless peculiar ; with some of them I am perhaps 

 even now acquainted, and in the event of your readers being at 

 all interested in the subject, I may trouble you with a longer 

 communication thereon at a later date. W. L. Scott. 



■WHY DO CLOUDS FLOAT? 

 Respecting the explanations offered* on the causes of the 

 Jloathig of clouds in the air, it may be mentioned that those 

 adduced by the writer would scarcely be adapted for the 

 different regions of the earth, though perhaps suited for this 

 country. The old idea of the vesicle is the more generally 

 useful form to consider cloud vapour as consisting of, as its 

 collapse, into a solid, forms the raindrop, which falls to the 

 ground by gravity. The vesicle will contain aqueous vapour 

 and heat derived from the seas, surrounded by a hollow cell 

 of water, as in a soap-bubble, and the flotation of this will 

 depend on the difference of specific gravity of these contents 

 and that of the external air. 



In equatorial regions the temperature of the seas may be 

 about 80°, while that of the sun in the superincumbent air 

 may be 100° at the cloud levels. The cloud vesicle would at 

 first contain vapour at 100°, enclosed in a capsule of water at 

 80°, and this would be maintained if the cloud remained 

 stationarj'. If the heat of the sun increased, then these 

 vesicles would rise by levity of contents and carrj- the clouds 

 into the upper levels of the atmosphere. If they reached the 

 levels of identical specific gravity above, and their envelope 

 became cooled and incohesive, then the cell would collapse 

 and fall down as rain. The white clouds in the equatorial 

 regions are either stationary or move upwards only, and re- 

 main for long periods suspended in immense woolly masses 

 in homogeneous temperatures. The persistence of clouds in 

 the temperate regions will depend on their continuing in the 

 body of the same wind, which though shifting its place con- 

 tinually, yet will remain of the same temperature for long 

 periods, and thus the cell contents will be kept at the same 

 levity and temperature. 



Clouds in tctnpcrate regions will be brought only from 

 southern and western quarters of the earth, as from these 

 only they could get cell contents of greater temperature and 

 levity than the atmospheres they ride in in more northern 

 latitudes. Hence, no clouds could generally be expected to 

 be derived from northerly or easterly quarters of the earth, 

 because the cell contents would be colder and denser than 

 the air they sailed in in southern regions. So that long ere 

 that they would have disappeared as vapour. 



The cloud vesicles may thus be considered as use- 

 ful microscopic balloons, and viewed as the means of trans- 

 porting the riches of heat and moisture from the tropics to 

 the desert regions of the globe, round the Arctic circles 

 north and south. 



These cell contents, when liberated by physical dissolution 

 of their envelopes, then fall to the earth as warm rain, and 

 likewise give out their caloric, when it is then sensibly felt in 

 the atmosphere. W. J. Black, F.R.M.S. 



ANSWERS TO CORRESPONDENTS. 

 John Lewis. — The subject of your communication is too 

 medical for discussion in our columns. 



* Scientific News, Vol. I., p. 9. 



RECENT INVENTIONS. 



The following list lias been compiled especially for the S}Clzvn:iviC 

 News, by Messrs. W. P. Thompson and Boult, Patent Agents, of 

 323, High Holborn, London, W. C. ; Neincastle Chambers, Angel 

 Row, Nottingham ; Ducie Buildings, Bank Street, Manchester ; and 

 6, Lord Street, Liverpool. 



Paper File. — A file for papers has been patented by- 

 Mr. A. E. Walker, of Milton Street, E.C. It is provided 

 with a spring clip, which has the advantage that the 

 clamping-bar when down holds the paper placed under 

 it with a firm grip, while it can easily be turned back, 

 thus taking the pressure completely oflT the papers, and 

 when lifted remains back automatically. The papers 

 can thus be referred to, and the clamp applied again. 



Toboggan. — Messrs. 'Whellans and Beswetherick, of 

 Dean Street, Soho, have patented a toboggan. The 

 object of this invention is to provide a sliding surface 

 in lieu of ice and snow. For this purpose tracks of 

 wood are provided, the tracks having rods of metal fixed 

 on their surface at suitable distances apart, either longi- 

 tudinally or transversely, for the toboggans to slide over ; 

 or, if preferred, the tracks may be faced with corrugated 

 metal. The toboggans are of the ordinary pattern, 

 except that they are faced with metal at the bottom to 

 suit the form of metal on the track. 



Gas Burner. — An inverted gas-lamp has been 

 patented by Mr. D. W. Sugg, of Vincent Street, West- 

 minster. The apparatus consists of an annular body, 

 which is placed in an inverted position, and is carried 

 by two hollow arms which connect the body with a 

 chimney, and serve as flues to conduct the products 

 of com.bustion to the chimney. The centre of this 

 body forms an air channel to the burner, and is 

 open to the external air, except that an adjustable outer 

 guard is employed to ensure an even and proper supply 

 of air passing to the air channel to feed the flame and 

 produce proper combustion. 



Oil Lamps. — Mr. E. Sundborg, of Mundella-road, 

 Battersea, has patented an improvement in oil lamps, to 

 prevent the bursting of the reservoir. For this purpose 

 there is made a safety opening on the top of the re- 

 servoir, provided with a spring valve, to prevent the 

 liquid contents from running out if the lamp be upset. 

 The spring valve or other covering is so arranged that 

 any pressure from sudden explosion inside the lamp 

 would open it and relieve the pressure, and there would 

 be no fracture and no conflagration. Old lamps may be 

 fitted with this safety valve. 



Fire-Proof Curtain for Theatres. — Messrs. Heath, 

 Kings and Geddes, of 46 Fairmead Road, Islington, have 

 patented a fire-proof curtain for theatres. A trench is 

 formed below the floor of the cellar close to the pro- 

 scenium wall, and a roller is placed therein ; above this 

 is placed another roller, round which is wound the fire- 

 proof screen. The screen is a canvas, and is carried 

 from the upper roller round and under the roller in the 

 trough ; the trough contains a solution of tungstate of 

 soda, which renders the screen impervious to the action 

 of fire. Immediately over the rollers is formed a narrow 

 hinged trap extending across the stage. A light iron 

 lattice girder extending the width of the curtain serves 



