U>7 9, 1867. ] 



JOUKNAL OF HORTICULTUEE AND COTTAGE GABDENER. 



333 



to. do what Mr. Thomson recommends. I should be glad to hear 

 how he explains this apparent contradiction. — Vixis, Lincoln, 



[In reply to your correspondent " Tins," allow me to say 

 that it was my brother and not I who had a controversy with 

 Mr. Rivers about layering the stems of Vines iu the soil at 

 planting. 



I am still of opinion, founding that opinion on extensive 

 experience, that mj' recommendation at page 28, as quoted by 

 " ViTis," is sound. If he will turn to " Experiments with 

 Vines," he will observe that I planted a house of Muscats at 

 Wrotham Park, in 1S17, exactly as he has done his. following 

 my advice; and if he will address a note to Mr. Edlington, 

 Wrotham Park, Barnet, who has the management of these 

 same Vines at this date, he will learn that more healthy, fruit- 

 ful Vines are rarely to be met with ; and at a distance of time 

 of twenty years, this is surely satisfactory evidence in favour 

 of the system of planting " Viris " has adopted on my recom- 

 mendation. I can give him scores of examples of the same 

 sort if he require them. — Wm. Thomson, Dalkeith Park.] 



THE ORIGIN OF COLOUR IN TRICOLOR 

 PELARGONIUilS. 



I HAVE read with great interest the very able remarks of your 

 correspondent " il.," at page 291, and perhaps you will kindly 

 allow me to thank him for his very courteous criticism of my 

 letter on the same subject in your impression of April 18th. 



Science, I am now aware, did not justify me in supposing 

 that brown and yellow would produce red ; but, paradoxical as 

 it may appear to be, ignorance in this particular instance 

 proved an advantage, as acting on this erroneous conviction, 

 and aided by some principle inherent in the leaf, but of the 

 natm-e of which and properties we are at present ignorant, the 

 desired effect has been produced. 



With regard to the Golden Tricolor Pelarijonium mentioned 

 by " M." as having been raised by Mr. Hally, of Blackheath, 

 some fifteen or tsventy years ago, and named Eriubow, I can 

 only say that I never saw it, and never heard of it before ; and 

 it certainly seems strange that this variety should have re- 

 mained in obscurity so long. Pelargonium Mrs. Pollock was 

 raised, I think, iu the year 1858, and when it was sent out two 

 or three years later, some one in writing upon the subject sub- 

 sequently, said, "that the advent of Mrs. Pollock literally tQok 

 the horticultural world as it were by storm." Tliat it created a 

 sensation is not to be denied, and it is really difficult to believe 

 that a variety quite equal to it, according to " M.," should have 

 been flourishing for so many years before that time at Deptford 

 or Blackheath, and yet for so very few people to have known of 

 its existence. I most sincerely trust, liowever, that " M." will 

 set the matter at rest by exhibiting a plant of this variety at 

 the exhibition of Tricolor Pelargoniums to be held at Kensing- 

 ton on the 21st of this month. 



I cannot at present refer to Mr. Pearson's letter, but I think 

 that he did not exactly say what " JI." says he did — viz., " that 

 no single plant of this class of Pelargoniums was antecedent to 

 Mrs. Pollock." I think he said, " that none worth growing 

 existed previous to the introduction of this variety." 



" M." is decidedly in error with regard to the origin of Italia 

 Unita. That variety was produced between a dark-zoned seed- 

 ling of my own, and a Silver Tricolor sort named Rainbow also 

 raised by myself. Rainbow was produced between Cerise 

 Unique and Attraction, and both the last-named varieties were, 

 I believe, raised by Mr. Kinghorn ; and the last-named (At- 

 traction) was. I believe, the first Silver Tricolor Pelargonium 

 produced. I have never once used Burning Bush for the pur- 

 pose of breeding. I am inclined to think that tiiere exist phy- 

 siological reasons for doubting the fact of a golden-margined 

 variety producing a silver-margined sport, but possibly I may 

 be wrong in this supposition ; but at all events the fact re- 

 quires confirmation. In the Gardmicrs' Chnmicle of last Sep- 

 tember I gave the pedigree of Pelargonium Mrs. Pollock, 

 which your correspondent " M." and other readers may not 

 have seen, so I will quote from a copy of my letter for their 

 information : — " The seed-bearing parent of Mrs. Pollock was a 

 variety called Emperor of the French, and the pollen parent 

 Gold Pheasant. The seed parent of Gold Pheasant was also 

 Emperor of the French, and the pollen parent Golden Tom 

 Thumb. The seed parent of Golden Tom Thumb was an old 

 variety called Cottage Maid, and the pollen parent Golden 

 Chain." The seed parent of Emperor of the French was 

 Cerise Unique, and the pollen parent was Attraction. The 



result of this cross was three distinct varieties produced on 

 line plant — viz., Emperor of the French, Empress of the 

 French (a marbled-stemmed variety like Cerise Unique), and 

 the Silver Tricolor variety called Rainbow. — P. Gbibve. 



The fact of being a near neighbour of Mr. Grieve for the last 

 dozen years enables me to write with some anthority on the 

 subject. There can be no question that to him belongs the rare 

 merit of originating most of the best varieties, and also of 

 having anticipated their production. His object from the first, 

 as frequently explained to myself and other friends, was two- 

 fold — to enlarge the size, and impart greater stamina to 

 (rolden Chain, and by an intermixture of blood between Golden 

 Chain and the Horseshoe varieties, to obtain new combi- 

 nations of colour. The appearance of Flower of the Day, and 

 other Silver-leaved sorts, turned his attention to the subject. 

 By crossing these with Zonals, and obtaining a pink zone, he 

 was easily led, as described by himself at page 275, to believe 

 in the possibility of producing Golden Tricolors; to secure this 

 object it seemed only necessary to pour golden instead > 

 silver blood into the dark-leaved Zonals. 



Such was Mr. Grieve's theory years ago, and I am not aware 

 that he has ever swerved a hair's breaUh from it since. The 

 results are before the world in such splendid varieties as Mrs. 

 Pollock, Lucy Grieve, Lady CiiUum, Mrs. Grieve, Mrs. Benyon, 

 ifeo. It matters little to the establishment of the point of designed 

 production, whether Mr. Grieve's views upon the effect of mix- 

 ing certain colours are scieutitically correct or not. It is suffi- 

 cient here to prove that he had a theory, that that theory, 

 right or wrong, aimed at a definite object — the production of 

 Golden Tricolors, and that his practice compassed that object. 

 Beginning with Golden Cliain and the best Zonal at command, 

 and then choosing the pollen of his own best seedlings as the 

 magic brush with which he has painted, he has succeeded in 

 originating and fixing more and finer colours on, iu, or about 

 Pelargonium leaves than any other grower of whom we have 

 heard. 



The difficulty of fixing the whereabouts of the colours leads 

 me to state that I think both " M." and Mr. Grieve treat the 

 general question of colour rather too mechanically. They 

 assume throughout that it is a substance, thus taking it for 

 granted that it is a quality inherent in bodies. This much 

 cannot be said to have been proven. Colour may be an optical 

 phenomenon — a matter entirely between the light of the sun, 

 a given surface, and the eye of the beholder — a question of 

 absorption, reflection, angles, or speed of dift'erent rays of light,, 

 and not one of physical structure. 



Or, assuming that colour is a substance, it is obvious that 

 it cannot be laid on living surfaces, such as leaves or flowers,, 

 as the artist spreads his colours on his p.alette, or the ex- 

 perimentalist evolves different hues, by placing the primary 

 colours in certain relationships to each other. We must not 

 overlook the disturbing power of vitality. Life is a fortress 

 too high for the dwarfed ladders of our knowleSge to scale, too 

 strong for our powers to carry by assault. We only know that 

 it is full of beauty, power, and mystery, and that it is under- 

 mined in all directions by distm'bing forces that bafHe our 

 wisdom ant defy our strength. Two of these forces that 

 probably exert as great, or a greater, influence on colour than 

 any mere mechanical depositions of tissue, coloured or other- 

 wise, are chemical action and vital force. 



Each plant is a miniature laboratory ; by the intermixture 

 of salts, acids, aud alkalies, plants probably manufacture 

 their own paint, as well as elaborate their inward secretions. 

 Light handles the brush, but the paint, if produced at all, is 

 most likely home-made within the plant itself. A familiar 

 instance of this chemical paint-making is seen in the appli- 

 , cation of alum or steel filings to Hydrangeas. It changes the 

 colour of the flowers from pink to blue. Doubtless this power 

 I which comes to the surface in this instance, is a powerful 

 ; thougti hidden colourist in myriads of other cases. 

 I Then there is the vital force. Its power, lilie its Author, 

 seems omnipotent. Perhaps it does all the colouring. How 

 I else shall we account for the capriciousness of its distribution, 

 ' or the regularity of its arrangement, or the sharpness of its 

 I limits ? Adverting only to the last, what peculiarity of struc- 

 ' ture or chemical action will explain our inability to originate 

 a blue Rose or Dahlia ? Or if it be contended that blue being 

 a primary colomr, no combination of other colours can pro- 

 duce it, aud therefore we fail, then I fall back upon the ex- 

 traordinary fact adverted to by Mr. Grieve — that lie has 



