HARD WICKE'S S CIENCE- G SSIP. 



75 



bottom of the vessels were cracked in eveiy direction. 

 In the month of September last (1877) I examined 

 some fragments of these deposits. I saw that the 

 frustules were there, and also that they were trans- 

 parent and apparently empty. But on making a 

 more careful examination, I saw in the interior of 

 one of the extremities, in a majority of frustules, some 

 brown granules, which I considered were the remains 

 of the dried endochrome. 



The vessels were then filled with distilled water 

 sufficiently aerated by prolonged agitation ; after this 

 they were exposed to the direct heat and light of the 

 sun. 



During the first two or three days there appeared 

 but little change in the frustules, but on the fourth 

 day the large brown granules had augmented in size, 

 and had taken the yellow tint characteristic of the 

 diatomaceous endochrome. In following from day to 

 day the augmentation of the plasma, I remarked 

 that on or about the fifth day this nearly filled the 

 middle of the frustule, and on the eighth day it had 

 assumed the normal form peculiar to the genus to 

 which the species belonged. The naviculas had re- 

 sumed their curious movements, and some days later 

 it became evident that a number of the frustules had 

 commenced to multiply by self-division. 



In the presence of these observations, we are able 

 to conclude that the diatoms, like many other of the 

 lower organisms, preserve the vegetative force in 

 spite of desiccation. At the same time I observed a 

 circumstance which deserves mention. In one of the 

 vessels a large number of diatoms were attached to 

 the sides of the glass : in these the endochrome never 

 returned to its normal condition. It is probable that 

 the plasma had been killed by too rapid a desiccation, 

 while the diatoms on the surface ■ dried less rapidly 

 as the substratum slowly lost its humidity : the 

 plasma was, therefore, able to contract slowly ; thus 

 preserving the power of returning to life under the 

 influence of favourable conditions. It seems, there- 

 fore, necessary, in order that the diatoms should 

 preserve their vegetative force, that the desiccation 

 should proceed slowly ; and that is exactly what takes 

 place in ditches and pools. After these facts, it is 

 easy to comprehend why, during the wet season, we 

 are able to find, almost directly, the diatoms for which 

 we have searched in vain during the drought." 



{A T ote by Translator. — These experiments will, I 

 think, not only account for the rapid reappearance of 

 the diatomacese in dried-up pools when these were 

 again refilled, but will also explain their presence in 

 such habitats as the moss on the trunks of trees, 

 roofs of cottages, or the damp places near leaky 

 water-butts or tanks. The debris from the dried-up 

 ditches is raised by the wind as fine dust, and carried, 

 perhaps, miles away, and after a time deposited in 

 the localities just alluded to ; the presence of moisture 

 not only soon restoring their vegetative power, but 

 enabling them to reproduce by self-division. 



Those who have examined gatherings from the 

 previously-named sources have, no doubt, been 

 struck with the absence of the larger forms : these 

 have, probably, been eliminated by their rapid sub- 

 sidence, owing to their much greater weight.) 



Norwich. F. Kitton. 



PRIMITIVE MAN : 

 HIS TIMES AND HIS COMPANIONS. 



By the Rev. J. Magens Mello, M.A., F.G.S. 



IN the history of almost all nations there is a point 

 at which that history loses itself in tradition and 

 myth, a point at which we should be left in im- 

 penetrable darkness were it not for the new light that 

 has been shed, at any rate, upon the past history of 

 man in Europe by the discoveries of the still young 

 science of Geology. When we attempt to trace back 

 the history of the human race in England, which we 

 may take by way of example, the earliest historical 

 records carry us back to the period of the Roman 

 Conquest ; the writings of the Roman Tacitus, and of 

 some other authors of that epoch, show us more or 

 less distinctly what kind of a countiy this was, and of 

 what sort the inhabitants were which they found in 

 possession ; and there history leaves us. We must 

 look elsewhere for any further information. That 

 information lay buried for long centuries beneath the 

 earth : in mounds, in caves, in gravel-pits the foot- 

 prints of primitive man were left for the explorers of 

 the 19th century to track and to interpret. 



During the last fifty years evidence has been fast 

 accumulating, showing us that long ages must have 

 elapsed, ages marked by many changes, since man 

 made his first appearance here ; evidence slowly 

 received indeed at first, but which has yet surely 

 made its way, forcing upon us the belief that long 

 before the Romans visited our shores, generations after 

 generations of men had come and gone, men to whose 

 eyes was presented a very different England to that 

 with which we are acquainted, men who had as their 

 companions animals very different to those with 

 which we are now familiar. What that England was 

 probably like, what those animals were, and what 

 little we know about those men is the subject of this 

 present sketch. 



Many ages before the Romans came there was a 

 time when England, instead of being an island, 

 together with Scotland and Ireland, formed part of 

 the continent of Europe ; there was then no Bristol 

 Channel, no Irish Sea, no Straits of Dover, no 

 German Ocean such as we now have them ; we must 

 picture to ourselves a northern and western extension 

 of the Continent with a great river, an enlargement 

 probably of the present Rhine, flowing northwards 

 through a wide valley or plain, where is now the sea. 

 Into this river flowed, as tributaries, the Thames and 



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