June I, 1 888.] 



SCIENTIFIC NEV/S. 



519 



its parents. It has a latent memory of their habits and 

 actions, which may be called into play by the stimulus 

 of circumstances. The possibility of latent memory 

 cannot be disputed. It often happens that we have 

 forgotten a name, a fact, an event, or a project, when 

 some casual incident, perhaps of a quite irrelevant nature, 

 brings it fully to our recollection. 



In a similar manner, according to Mr. S. Butler's theory, 

 when a pair of young birds have mated, the latent 

 memory of the nest-building art which they inherit from 

 their forefathers is called into action. Or the female 

 solitary wasp, when about to oviposit, becomes con- 

 scious of the architectural traditions of her species, of 

 which she had previously only a latent unconscious 

 knowledge. 



This explanation, if it can be reconciled with all the 

 facts of the case, must complete the long wished for 

 decomposition of the instinct hypothesis, notwithstanding 

 those phrenologists who allege that they have discovered 

 an " organ of instinct" in the brain of certain animals. 



EXCEPTIONAL METEOROLOGY. 



FOR the last two or three years there has been 

 exceptional weather over a large area of the 

 northern hemisphere, with excessive rain, causing floods. 

 These excesses are not uncommon, when time is con- 

 sidered, as history details such at intervals of centuries; 

 and geology indicates similar excesses during cycles of 

 centuries. Wide variations in the seasons over the 

 earth's surface can only come from cosmical causes, the 

 prime source of heat being the sun. Our earth only 

 receives a small fractional part of the sun's heat ; but, 

 whatever that may be in the year, more or less than 

 the average, the entire surface of our earth must feel 

 and be subject to the effects. And one thing is certain — 

 namely, that a year, or series of years, of excessive sun 

 heat will inevitably be years and seasons of excessive 

 atmospheric disturbances, because increase of heat will 

 produce excess ol evaporation, excess of electric action, 

 and, necessarily, excessive precipitation ; and, during a 

 prevalence of this excess of sun heat, there must be over 

 limited areas violent storms both summer and winter. 



A high temperature over sea and land will produce an 

 excessively vapour-saturated atmosphere, beneath a 

 colder atmosphere above, making, during a calm, a 

 dangerously unequal balance, as there may be a lower 

 stratum of atmosphere at upwards of 100 degrees of 

 temperature, holding in solution transparent vapour, 

 containing near i,coo degrees of latent heat. When, 

 therefore, very large areas of the atmosphere have been, 

 by excess of heat, brought into an unequal state, as large 

 areas of lower stratum of highly heated air and vapour, 

 which is also intensely electric, the conditions to produce 

 sandspouts, waterspouts, and tornadoes are fully ripe. 

 The upper and colder layer of the atmosphere cannot 

 cool the lower higily heated and vapour laden stratum 

 so evenly and quickly as to prevent vents in the form of 

 funnels forming from the lower stratum to the higher 

 stratum, and causing a rupture which takes place upwards 

 in a pipe-form, just as water in a tank or basin, having 

 a bottom means for discharge by a pipe, flows out with a 

 whirling motion — in our northern hemisphere always in 

 the direction of the hands of a clock, and so the heated, 

 highly electric, and excessively vapour laden atmosphere 

 breaks into the cold atmosphere above when at the level 



of the " dew point," invisible vapour becomes visible, 

 parting witli its latent heat, which so rarifies the air as 

 to force some of the condensed atmosphere in visible 

 cloud mounting thousands of teet above the condensing 

 dew point, and into a region above the highest peaks of 

 the highest mountains ; and to feed this pipe, or, as in 

 some rases, pipes, the lower stratum flows in from all 

 sides to rotate and ascend with the intense velocity of 

 steam power, sufficient to produce all the disastrous 

 effects of the wildest tornado, there being almost a 

 vacuum at the ground, or water line, as the phenomenori 

 may be on the land or over the sea. On the land trees 

 are twisted and uprooted, houses are unroofed, solids of 

 various kinds are lifted from the earth, and human beings 

 have been blown away like dead leaves. There are, also, 

 records of railway waggons having been blown off the 

 rails. In desei-ts, entire caravans have been buried 

 beneath a mountain of blown sand, camels, horses, and 

 men ; while in Egypt there are the ruins of cities, massive 

 temples, and monuments deep buried in the adjoining 

 desert sand. At sea many a good ship caught by a 

 tornado has been overwhelmed and sent to the bottom 

 whole. 



These violent tordado storms are intensified types of 

 storms in general, which may be more miles in width 

 than a tornado is yards, but there is a similar process, a 

 flowing in from all sides towards a revolving centre with 

 an upward flow of heated air to the dew point of con- 

 densation, and an out and over roll above of visible 

 vapour, giving a high barometer over large areas all round 

 the storm, with fog. There are, however, milder forms 

 of the described action, producing on a warm summer 

 day the cumulus clouds. Here the lower stratum of 

 warm air is also flowing inwards and rising upwards 

 beneath each cloud, condensing at the dew point, part- 

 ing with latent heat, producing modified steam power, 

 and so causing these summer clouds to enlarge upwards, 

 bulge, and mount in sunshine like illuminated Wool- 

 pack Mountains. — The Times. 



The Natural Law of Relation between Rainfall and Vegetable 

 Life, and its Application to Australia. By Franz A. 

 Velschow, C.E. (of Copenhagen). London : Stan- 

 ford. 

 Are certain regions of our globe barren, or at least 

 poor in vegetation, from the paucity or the irregularity of 

 the rainfall ? Or is the drought the consequence of the 

 deficiency of vegetation, or of the presence mainly of 

 such trees and shrubs as are of a desert type ? Which of 

 the two sets of phenomena is cause, and which is effect ? 

 Common opinion asserts that rainlessness gives rise to 

 treelessness, and that if we could pour down upon the 

 Sahara, upon Arabia, and the central regions of Australia, 

 a yearly and evenly distributed rainfall of 50 or 60 

 inches, we should see them covered with a luxuriant 

 vegetation. 



Our author takes the opposite view. He considers 

 that the regions in question are arid either because their 

 forests have been recklessly felled, burnt down in times 

 of war, and destroyed by goats, which Sir Joseph Hooker 

 pronounces to be worse ravagers then war. Or, where 

 there has been no such general and wide-spread des- 

 truction, the natural vegetation, as in Australia, is not of 



