Collingwood <1>
April 6/41
My dear Sir
Your news is exciting indeed but I confess I am not sanguine of its verification yet there is a feature in one part of the statement that makes it plausible.– Boron and Silicium have a great general analogy with Carbon and their atomic numbers are so nearly equal that (considering the extreme difficulty of analysing Silex & B. Acid <2> or recomposing them out of oxygen and their radicals, which leaves room for a good deal of adjustability in the numbers) it is not at all implausible that they are really isomerisms of one radical. – Among the metals Cobalt and Nickel have always appeared to me as almost certainly twin-elements: modifications of one common principle. Their numbers (29·5) agree precisely. And Iron which of all the metals has the greatest analogy with these and with which nickel especially agrees in being magnetic, has its number 28 wh is very near. Then comes manganese (of the same family, but with a farther shade of departure) 27·7.
In the same line of speculation must be noticed the very singular relations subsisting among the metals associated with Platina which form two groupes <3> thus
| Platina = 98·6 | Palladium = 53 | |
| Iridium = 98·6 | Rhodium = 52 | |
| Osmium = 99·… |
That these coincidences should be accidental seems hardly admissible – but that the 3 bodies of the 1st groupe should on this our globe, be always found in conjunction – and yet be as they are the rarest bodies in nature and so oddly distributed – does look very suspicious On the other hand though I do not know that Rhodium is al accompanies Palladium in the South American Gold, it is curious that here we have a case in which the [illegible deletion] a body of the 2d groupe is found disjoined from the first.
Again the analogy of Lead and Silver is marked and their numbers 103·5 and 108 are near together.
Again if we pack together the Precious & heavy metals, unoxidizable by heat alone, thus
Iridium 98·6
Platina 98·6
Osmium 99·0
½ Gold 100·0
½ Mercury = 100·0
2x Rhodium 104·0
2x Palladium 106·0
Silver 108·0
We have an analogy which is not much more farfetched than some other speculations in Chemistry which might be named
The Numbers of Lithium & Magnesium differ a good deal 10·0 & 12·7 but they adjoin in the scale of atomic numbers and Lm was by Arfvedson <4> confounded in its properties with magnm till weighing shewed him a difference & led to its discovery.
Phosphorous was originally regarded as a sort of sulphur. Their numbers are 15·7 and 16·0. Their chemical properties also stand in remarkable accordance – the chief difference consisting in a tendency to a different set of atomic combinations with oxygen and in a tendency in the former to isomeric equivoques <5> which the other does not shew. Might not one of these bring it actually into the state of Sulphur?
I think I some time last summer sent you a Pink Lady <6> – but it was a bad specimen. That which I meant to have sent was at the time mislaid. Two or three days ago it turned up in the leaves of a book and I now send her for your inspection. The colouring matter is the juice of the red double stock. The most sensitive vegetable matter I have yet met with is the green juice of the red cabbage – the action is very slow * – but attended with some curious phenomena
If I recollect right this Lady was a week and upwards in the Sun.
One peculiarity in all actions on vegetable tints which I have tried is that the action seems proportiona [illegible deletion] nearly limited to the luminous rays and is a maximum in the yellow. Another is that the discharge of colour is not complete – the red rays disclose or produce a red-ness and the blue a blueness in the residual tint. This taken in connexion with the phenomenon of argentine salts indicates a colorific power in the rays and independent of the themselves analogous to their own tint which on such different substances is very curious.
Pray send me back my Pink Lady as she forms a part of a series
I enclose a further dialogue <7> on Space and infinity which as you will see by the date was intended to have been sent before this. I thought you must have had enough of the first. However as you refer to the subject again it shall go.–
Believe me My dear sir Yours very truly
JFW Herschel
Notes:
1. Hawkhurst, Kent.
2. Boric acid.
3. Herschel retains the French spelling throughout.
4. Johan August Arfvedson (1792–1841) discovered the element lithium in 1817.
5. Ambiguities.
6. An experimental colour photograph, made from copying an engraving of a woman. [See Doc. No: 04129].
7. See the dialogue in Doc. No: 04228, dated 25 March.