So 



HARD WICKE'S SCIENCE- G OSS J P. 



mechanical power. In the paragraph where I found 

 the suggestion it is truly added that "it would be a 

 novelty to have the ballast weighing the anchor or 

 hauling at the ropes." The probability of this 

 however, is very remote, as the conversion of the 

 mechanical power of the engine that drives the 

 dynamo into electrical energy, and the reconversion of 

 this back to mechanical power is a roundabout and 

 costly proceeding The conversion of the engine 

 power into light is very different in places where 

 cheap gas is not obtainable. Paraffin lamps are 

 objectionable on board ship, and the ordinary colza 

 oil ship lamps are very costly in working, many times 

 more so than gas in town. The electric light on board 

 ship is a most desirable luxury, and compared with 

 other available sources of light, is the most economical. 

 It is rapidly coming into general use. 



The Rings of Saturn. — There remains now 

 but little doubt concerning the nature of these 

 marvels of the heavens which so long have puzzled 

 astronomers. They cannot be the solid flat hoops 

 that they appear to be, as they are too thin in pro- 

 portion to their other dimensions to retain their 

 stability against the gravitation of their primary. 

 The idea that they are liquid comes to grief still 

 more hopelessly. 



But they may be, and in all probability are, a 

 multitude of small satellites which, seen as we see 

 them with their interspaces foreshortened, need not 

 be very close together to appear continuous. To 

 understand this, place yourself at night on Constitution 

 Hill, Piccadilly, or on any other street where you 

 command the view of a row of gas lights half a mile 

 long in foreshortened perspective. It will then be 

 seen that the distant gas lights appear to touch each 

 other, to form a continuous line instead of a row of 

 luminous dots, as do those which are nearer, or are 

 viewed more athwart the line. 



Further evidence in support of this view of the 

 constitution of the rings is continually coming forward 

 in observations of changes among the rings. Thus 

 the observations of Paul Stroobant (" Bulletin de 

 l'Academie Royale de Belgique," November, 1887), 

 extending from January 27th to April 20th, show 

 that the divisions known as Encke's and Struve's are 

 subject to considerable changes of position, and to 

 occasional disappearance of one, while the other 

 remains visible. The changes of the inner dusky 

 ring are still more remarkable, and indicate extreme 

 mobility of its constituents ; suggesting the idea that 

 it bears a relation to Saturn similar to that of the 

 zodiacal light to the sun. 



C. Edusa. — Can any of your correspondents tell 

 me if this insect has been taken in this district during 

 the past season ? I have not heard of a single specimen 

 being seen for several seasons. — C. S., Penarth, near 

 Cardiff. 



DRYING PLANTS ON A TOUR. 



IN the November number of Science-Gossip there 

 is a paper by M. Copineau, " On Drying of Plants 

 on a Tour," in which he states that it is of the greatest 

 importance that they be dried quickly, and never 

 be allowed to remain in damp paper. Every one 

 I believe, will agree with this statement, but few, I 

 imagine, will admit that he has hit upon the best 

 means to attain this most desirable end. My idea 

 is that, for the speedy drying of papers, it is most 

 essential that every sheet should be separated, and 

 that no greater mistake can be made than by sewing 

 eight or ten thicknesses of paper together, and so 

 forming a pad. I do not either like the form of press 

 he recommends, so will proceed to describe the 

 methods I have adopted. 



When I start on a fortnight's tour, I generally take 

 a supply of drying paper about ten inches in depth, 

 this I find amply sufficient for the first few days, and 

 it allows of changing the plants into fresh paper every 

 night ; my last performance before getting into bed 

 is to begin in one corner of the room and stand 



Fig. 35- 



all the damp papers up on end, and by morning I 

 find they are quite fit to use again. At first sight it 

 may appear rather difficult to stand up limp paper in 

 this manner, but there is really no difficulty about it, 

 by maintaining the fold in the middle of the paper 

 and curving back the edges so that the plan gives 

 somewhat the outline of the figure 3, one is made to 

 support another with the least amount of contact. Of 

 course, I will at once admit, it adds nothing to the 

 tidiness of one's bedroom, but after a long day's 

 tramp, I have never found this interfere in any way 

 with my slumbers, and I can guarantee its efficiency. 



There is perhaps no better way of drying papers 

 than laying them out singly in the sun, as by the time 

 the last one is disposed of, the first is quite dry 

 enough to be taken up again. I confess, however, 

 when the sun is shining I want to be doing some- 

 thing else, and it is not always safe to delegate the 

 work to others. 



I have made modifications in my presses from 

 time to time, and the one I use for travelling, to me 

 seems a very efficient one, and has been copied by 

 several of my friends. It consists of two boards 



