HARDWICKE'S SCIENCE-GOSSIP. 



27 



observations of instruments and observations of the 

 clouds. 



Part II. of the book is advanced, and contains 

 fifteen chapters. The headings of a few of these 

 chapters will give some idea of their contents : Wind 

 and Calm, Heat and Cold, Squalls and Thunder- 

 storms, Whirlwinds and Tornadoes, Types and Spells 

 of Weather. 



After describing very clearly how isobars are 

 formed, the author shows the relation of the velocity 

 and direction of the wind to them, and the influence 

 of different shapes of isobars in modifying the distri- 

 bution of heat and cold from day to day in various 

 parts of the world. Then the supposed relation 

 between sunspots and rainfall is considered, and it 

 is pretty clearly shown that no connection can be 

 traced between them. For instance, in the year 

 1S72 — a year when there was a maximum of sun- 

 spots — Buchan plotted the rainfall of Scotland, and 

 found that while near Aberdeen the rainfall was 

 seventy-five per cent, above the average, the amount 

 of rain at Cape Wrath, about one hundred miles 

 distant, was below the average. The author justly 

 inquires why we should take the returns of one 

 station more than another to compare with sun-spots, 

 seeing that they should affect the whole world 

 simultaneously. 



In a book on weather prediction so complete, it is 

 curious to find no reference to the use of the Rain 

 Band Spectroscope for predicting rain locally. Those 

 who have tried the instrument know that it is of the 

 highest value for this purpose. 



Writing now on the evening of December 4th, the 

 barometer has been falling steadily since mid-day on 

 the 1st instant — that is, successively night and day 

 for three days. This morning, about 8 A.M., the 

 clouds were very low and threatening, the atmosphere 

 near the earth clear, so that hills six miles off were 

 seen sharply defined ; every appearance would have 

 induced one to believe that rain was imminent. On 

 observing the spectrum with the spectroscope, I 

 found an almost total absence of the rain band ; 

 indeed, there was so little that only a well-trained 

 eye could have detected it. No rain has fallen 

 throughout the whole day. 



I have in my mind a case of positive prediction 

 instead of negative, perhaps to many still more 

 convincing. On the eve of a Bank Holiday recently, 

 one of my friends, who had come into the country to 

 stay with me for several days, said to me, "We are 

 going to have a glorious day to-morrow." My reply 

 was, " I am sorry to say we shall have a wet day to- 

 morrow." "Nonsense," said my friend, who is 

 something of a meteorologist, "the barometer has 

 been rising for the last day or two, and we had a 

 beautiful pink sunset." My answer was, " There is 

 a strong rain band in the spectrum." The next 

 morning, soon after 8 o'clock, it began to drizzle ; 

 by 9 o'clock it was raining pretty fast, and it pouied 



almost continuously during the whole day. It would 

 be easy to multiply such instances to almost any 

 extent. 



Few persons are aware that a barometer rises very 

 quickly an hour or two before a thunderstorm. This 

 can seldom be observed, excepting on the diagrams 

 taken with a self-registering barometer. A capital 

 illustration is given in " Weather," by means of 

 photography, from one of these diagrams. This 

 sudden rise is mostly followed by two or three V's, 

 resembling several reversed W's, with the V's be- 

 coming smaller and smaller, thus — MM.> but the V's 

 irregular in size. 



It is pretty well known to my friends that I sleep 

 so soundly that no thunderstorm will wake me. On 

 one occasion recently, at the breakfast table, I was 

 told there had been a thunderstorm in the night. I 

 immediately replied there had been two, about three 

 hours apart. ' ' How can you know that, when they 

 never wake you ? " was the inquiry. I told them 

 that before I dressed I had consulted my self- 

 registering barometer. As no one in the house had 

 heard the two storms, my information was evidently 

 doubted. Shortly afterwards a friend came in, who re- 

 ferred to the two storms, and said they were about 

 three hours apart. 



Considerations of space will not permit me to give 

 an adequate idea of the matter in the volume, which 

 consists of about five hundred pages, and contains 

 nearly one hundred illustrations. It not only brings 

 together all the knowledge we at present have on the 

 subject of the weather, but it gives also the results 

 of the author's original and unpublished researches, 

 which are of great interest and value. 



Mr. Abereromby's book is indispensable to all 

 who wish to understand the present position of 

 applied meteorology, as exemplified in weather 

 forecasts. 



John Browning. 



CHATS ABOUT ROTIFERS. 

 (Ertemias tetrathrix.) 



THIS singular and rare rotiferon has been classified 

 as belonging to the family Anurcedse, genus 

 Ertemia (Gosse). 



The lorica is smooth, and shaped like a deep 

 obconic wine-glass, of which the foot is represented 

 by a long attenuated rigid bristle. Three similar 

 bristles project from the front edge of the lorica. 

 The centre bristle (the longest of the three frontal 

 ones) springs from the dorsal margin, and is about 

 one-fifth longer than the two side bristles. 



The head is projected a short distance from the 

 mouth of the lorica, and crowned with a wreath of 

 closely set vibratile cilia. 



C 2 



