Courage, hope
Compounded in a potion
So heady strong
It bursts all barriers
Sweeps on
Transforming dust
To love
Let me wave the wand
For you
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This is magic: Courage, hope Compounded in a potion So heady strong It bursts all barriers Sweeps on Transforming dust To love Let me wave the wand For you |
| date | 2000-11-12:14:31 |
| Creatures |
Charismatic megafauna are all very well, but what about the smaller creatures around us? There are a lot more of them, and their diversity is amazing. Sitting on the front step this morning, catching some rare November sunshine, reading a book and drinking a cup of tea I noticed two varieties of spider and at least four different types of fly. Three of the flies had the courtesy to land on my book or sleeve for long enough to let me examine them closely, which is something you don't usually get to do with the larger creatures. There were two types of house-fly amongst my vistors, one small and one large. The large was was dark, almost black, and didn't stay long enough for me to get a close look. The smaller one came back several times, in the guise of several different individuals (this is the way a Platonist would say it--if only the Forms are real, then we never see individuals, but rather Forms in the guise of individuals. The Form can exist without the individual, and not the other way around.) The smaller one was dull gray or brown, with a small head, grey/brown hairy thorax and grayish, irridescent abdomen. The abdomen had the appearance of being covered in a series of overlapping plates, like a chiton or trilobyte. Plating is one of the basic solutions to the problem of how animals with external skeletons grow: the plates themselves can grow and so allow the whole body to expand as the animal gets bigger. The other solution, adopted by crabs for example, is to shed the skeleton at intevals, having secreted a softer new one underneath the old, which expands and hardens after the moulting has taken place. The most interesting thing about the small house-fly was its wings, which at rest formed roughly a delta-shape, with connections to the back of the thorax. The thing that I found interesting, which I'd never noticed before, was that at the point of connection there was a tiny upright winglet, less than a tenth of the size of the main wing. At first I thought it might be a sport, as I could only see one on the fly I initially noticed it on, but looking more carefully I could catch the other in the sunlight, and another fly that landed later had them as well (I know it was another fly because at that point there were two of them on my book, and both had the little winglets, and one of them must have been other than the one I'd seen before.) I presume the winglets have some important areodynamic role, probably to do with stability or efficiency. I have no idea how a fly's wings move in flight, so I have no idea how they might fulfill that role, but it was still a nice reward for my close examination. Here's an unrelated question: what is the dynamic range of a fly's eye? How do they, in the absence of eyelids, cope with conditions ranging from full sunlight to very dull evening light? The second type of fly I got to examine closely was a bee-fly. As the name suggests, these have a striped abdomen, similar to that of the common or Italian honey bee. Bee-flies are quite a bit smaller than the average honey bee, but have similar proportions. Their wings, unlike the house-fly's triangular ones, are rounded, elongated ovals that narrow to a thin ithsmus connecting them to the forward part of the thorax. There's obviously a great deal of room for areodynamic optimization amongst creatures of this size; much more so than in birds: the wings of any two birds of about the same size as each other will be much more similar to each other than the wings of these two flies were. The scope for variability is due to the cube-square law, which is just the observation that as the linear dimensions of an animal increase its mass increases as the cube of its size, but its strength increases as the square, because strength depends on things like the cross-sectional area of muscle, or the area of the wings in the case of flying creatures, while the mass depends on the volume of the creature. |
| Reading |
Homer has a great deal in common with a well-made action-adventure film, something that entertains primarily through repetitious and artistically rendered violence. It's good to see men fighting with gods, but it's typical that the only god who gets hurt is the goddess of love. In lighter fare, I picked up Bruce Alexander's Blind Justice a few days ago. Well-written historical novels can be a useful adjunct to historical reading--Mary Renault's Fire from Heaven for instance provides a very nice background to Robin Lane Fox's Alexander the Great. Any historical novel needs to be read with an understanding of the time and place, and they are a terrible way to actually gather a semblence of historical knowledge, but they can have a useful place in understanding other times. Their greatest defect is anachronism--too many authors simply transport modern sensibilities to different historical locales, and that is exactly what you want to avoid. Blind Justice is set in the England of the late 1700's, between the American Rebelion and the Napoleonic wars. It deals with Sir John Fielding (purported brother of Henry Fielding, whose novel Tom Jones is next on my list of things to read after the Iliad--I have no idea of his historicity) and provides a moderately good view of civil life at that time, which will be known to most people through Boswell's Life of Samual Johnson. I've read only bits of the latter work, and Alexander's depiction of Boswell as a gossipy bore certainly matches my impressions from the little I've read, notwithstanding his sometimes brilliant anecdotes. |