Another common point is the mention of isolation in both of these excerpts (which maybe are here to help the expert to realise a better observation of the theme presented). Indeed, in the second passage, we notice at the beginning a series of names (“William Withycombe, Alex Shawe, John Dawe, William Friend”) preceding two words: “and I.”. This suggests an exclusion, an isolation, as if the narrator was and/or wanted to be apart from the others. In parallel, we read in the first passage the very first verse in which he says “shhh I can make myself invisible”; this verse suggests an atmosphere of silence and solitude. So we can conclude that he really needs to be alone, maybe to do his job effectively and obtain what he wanted by observing the nature, in silence.
So as we can see, these passages have common points, but they also have many differences.
Firstly because the first passage concerns nature, the voice of the poem seems passionate and blended in with nature, while the second passage is more about machines, it is more technical and industrial. By the way, the verse “reasonably biodegradable” means the operation isn't totally biodegradable and so it pollutes water, which actually is a serious issue for the naturalist. In this extract we hear a more complaining voice, as if the narrator is conscious of this pollution problem and feels responsible for it. Still in this passage, we notice a little touch of humour: “Unfortunately sheep don't use loopaper.”, which actually breaks the rhythm of the poem. In opposition, we don't notice any humour in the first extract, and this shows some serious talking and it will keep the harmony at best.
In fact, there is a very discrete common point between the two excerpts which actually seems to turn out into a difference: in the second passage we can read near the end “That smell of old wet sheep”; this verse provokes, of course, a reaction of disgust. However, there is the same kind of disgusting expression in the first passage -as for example “moist places”- though this time the reaction of disgust seems surprisingly absent. So, naturally, both of these expressions are disgusting, but it is easier to feel it in the second passage rather than in the first one.
Another difference is the environment in which the scenes are described; passage one shows an image of nature, without any machines or any polluting aspect, but it also shows harmony with nature and the simple act of observing the beauty of the nature itself. Contrarily to this, passage two offers a more factory atmosphere, with -this time- machines and pollution; there isn't any positive relation or harmony with nature. So this is an important and remarkable difference between these two extracts.
And finally, the last difference is that for each of these passages, we find its proper aspects; passage one delivers natural aspects, as well as nature observations: “I saw it eat an eel alive”, “I can see frogs hiding under spawn”. And passage two gives us more technical and chemical aspects: “spinning at 5,000 rotations per minute”, “it's relatively free of calcium”. So this really shows each extract has its own theme and specific images.
To conclude this, we can say that these two passages from Dart are indeed conflicting and have many differences and their own aspects and themes, even if some common points are noticeable, and this is maybe what links them with each other and help in the effectiveness of the construction of the whole poem.