HARD WI CKE ' S S C1ENCE- G SSI P. 



2S1 



loosened ; in fact, I have the stump still. Is the 

 property attributed to the mudar entirely mythical, or 

 is its having no effect on me to be attributed to 

 personal idiosyncrasy ? — y. R. Holt. 



Double-flowered Rose. — In last month's num- 

 ber of Science-Gossip I notice a letter from Mr. 

 W. H. Grattan, relative to a curious flower of the 

 dahlia. I have never seen this remarkable freak in a 

 dahlia, but I do not think it is very uncommon in 

 cultivated roses. On several occasions I have had 

 double-flowered roses, generally what are known as 

 "tea-roses," sent to me. The last occasion was in 

 August, 1S91, when I had two very fine examples 

 forwarded to me from the Isle of Man. In both 

 cases the lower bloom was fully expanded, while the 

 upper, which grew from the centre of the first, was 

 only half open, and somewhat smaller than the 

 other. — L. Crcaghc- Howard, Weybridge School, 

 Surrey. 



"The British Moss-Flora." — Dr. Braithwaite 

 still manages to find time to bring out his noble 

 work. The fourteenth number is to hand, dealing 

 with Family XV., Bryacea, II., doubtless the most 

 interesting as well as the most beautiful family of our 

 moss-flora. The present number contains six plates, 

 crowded with the characteristic details of the struc- 

 ture of each species, which are as artistically exe- 

 cuted as they are microscopically accurate, which is 

 saying a good deal. 



Vars. of British Plants.— I was very pleased 

 to see Mr. Bennett's article on new varieties of 

 British plants, but it would have been much more 

 valuable if accompanied by short descriptions of 

 some of them, which are only described in Exch. 

 Club Reports, or periodicals which dwellers in 

 remote country places are not likely to have access to. 

 Please do not look upon this as a " grumble " — quite 

 the reverse. I think Science-Gossip has never 

 been so useful and interesting as now. — y. A. 

 Wkeldon. 



Colouration in Plants. — On reading the in- 

 teresting paper in the October number of Sciexce- 

 GossiP,on "The colouration of the rose, the violet, and 

 the buttercup," a question occurs to me that I should 

 much like to have answered. Why do some blue- 

 coloured flowers lose their tints in drying, whilst 

 others are steadfast in retaining them ? I take two 

 constant examples. It is next to impossible to 

 obtain a dried specimen of the Campanula rotundi- 

 folia with its colour, which from its stiff, wire-like 

 stem and dry leaves, and its flowers which rattle 

 together on shaking the bunch, you would expect to 

 keep their natural tint, though they completely lose it, 

 leaving the bells a transparent white. Perhaps one 

 may succeed in obtaining one specimen out of a 

 dozen with a blue bell on the plant. All the 



campanulas are equally disappointing, as far as my 

 experience goes, while the gentians of every sort 

 keep their beautiful full colour even with the most 

 careless drying. I have specimens of the Gentiana 

 pneicmonanthe, the marsh gentian, dried more than 

 three years ago, and other sorts twenty years ago, 

 dried in Switzerland, all as blue as when they were 

 gathered. Now, what is the difference of these two 

 blue tints ? Must there not be a radical difference ? 

 A very curious — accident, I must call it — happened 

 to me last summer. I hurriedly put a piece of 

 Campanula rotundifolia into the book I had in my 

 hand, between the cover and the fly-leaf, the inner 

 lining and the fly-leaf being of a dark blue-green, and 

 to my surprise, on opening the book a week or so 

 later, I found my Campanula there, and to my 

 greater surprise, the three blossoms and several buds 

 had dried blue ! I had then left the country and had 

 no further opportunity of experimenting. I enclose 

 a bit of the fly-leaf. Could the colour or dyeing 

 of the paper have had any effect in the fastening of 

 the blue in the flower ? — /. G. 



GEOLOGY. 



The "Geology, of London." — Referring to the 

 admirable article on the geology of London, which 

 appeared in your last issue, may I quote a passage 

 from Mr. Whitaker's " Guide to the Geology of 

 London," 5th ed., p. 22, which appears to me 

 practically to settle the question, whether the 

 doubtful beds found in the Kentish Town, Crossness, 

 or Streatbam borings, belong to the old red sandstone 

 series or not. He says "There is a reason against 

 the classification of the bottom beds at Kentish 

 Town and Crossness with the old red sandstone, 

 which seems to have escaped notice before the 

 publication of the 3rd ed. of this work. Having that 

 series unmistakably present in the Devonian type at 

 Cheshunt and at Meux's, it would be strange indeed 

 were it to occur in its wholly distinct old red type 

 at Kentish Town, between those two places, and at 

 Crossness, not many miles from the latter of them. 

 I believe that such a thing is, at all events, very 

 unusual, the two types of what is generally taken to be 

 one great geological system being limited to separate 

 districts, and not occurring together," et sea. This 

 is certainly a very forcible argument, and if we 

 accept it as practically conclusive, the point at issue 

 is narrowed down to a decision between the carboni- 

 ferous and triassic ages. The former of these appears 

 to be out of the question, so that there is nothing 

 for it but to class the doubtful beds as triassic. In 

 doing so, however, in the absence of positive proof, 

 we should of course, have to be prepared for a 

 surprise, should a subsequent boring show that 

 this is really a very exceptional case. — Llesba. 



