70 



HARDWICKE'S SCIENCE GOSSIP. 



podes, and hearing Royalty, while there, has had 

 some like them set as sleeve-links,' &c.,_ we have 

 only too gladly availed ourselves of the hint. And 

 now, will some kind reader of Science-Gossip 

 help us to the true name of the shell owning such 

 a wonderful eyelid ? — J. W. K, 



The Depth op Soil in Cornwall, over hill 

 and dale, will average about one foot. Supposing 

 a beech-leaf to cover a superficial inch, it takes 

 about 35 dead brown leaves, tightly consolidated 

 by pressure in a hand-vice, to form \ of an inch in 

 substance, which multiplied by 8, gives 280 years, 

 necessary to yield one inch of ground ; which, 

 again, multiplied by 12, gives a lapse of time of 

 3,360 years to produce one foot of vegetable soil. 

 Allow another preliminary space, of a few hundred 

 years, for the annual growth and decay of the first 

 scanty covering of lichens and mosses, a period of 

 time of about 4,000 years would pass before the 

 bald hills of a bare world could screen their naked- 

 ness from view, clothed in the leafy foliage of 

 nature.— W. B. Fowey. 



The Tamarisk Manna.— I think your corre- 

 spondent "C." will find a perfectly authentic 

 description of this tree in a work entitled " The 

 Desert of Sinai," by Bonnar. The Tamarix manni- 

 fera drops in the summer a sort of substance called 

 by the Arabs "Mann." This "Mann" falls from 

 the leaves on the ground beneath the tree, and it is 

 soon collected by the Bedouins, who eat it with 

 bread. Many persons affirm that "Mann" does 

 not exude from the trees at all, but that it is formed 

 by an insect which abounds in the Tamarix. Others 

 say it is this insect, one of the Cocci, that makes a 

 puncture in the bark of the tree, from which the 

 juice exudes, and, becoming concreted, falls in the 

 form of manna to the earth ; whilst a few travellers 

 assert that the manna of the Jews was produced 

 by a species of camel's-thorn {Alhagi maurorum). 

 Bonnar is a living writer, and, to the best of my 

 recollection, he mentions having seen the manna of 

 the tamarisk.— Helen E. Watney. 



Forest Fires in the United States.— In many 

 places large tracts of forest_ have been burnt down 

 from the carelessness or mischief of hunters, who 

 take no trouble to prevent the destruction of the 

 forest by the camp fires. They even_ wilfully set 

 fire to a tree when entering the forest, in order that 

 the smoke may guide them out again, Few sights 

 are more dreary than that of a burnt forest with 

 the charred and blackened trunks of trees, some 

 still standing, and others tumbled about in the most 

 fantastic confusion.— Townshend, "Ten Thousand 

 Miles of Travel" 



Natural Selection (p. 42).— There is nothing 

 remarkable in the circumstance of the water-hen 

 taking refuge in a tree, as mentioned by " G. G.," 

 under the above heading. Every one who has 

 watched the manners of these birds is aware that 

 they are in the constant habit of roosting on boughs 

 overhanging pieces of water. I have myself many 

 a time disturbed them, late in the evening, in such 

 situations, and have watched them fly hurriedly 

 downwards, until thev reached the surface of the 

 water. If " G. G." will refer to Yarrell's "British 

 Birds " {sub voce), he will find an instance given of 

 a water-hen nesting "in a spruce fir tree, twenty 

 feet from the ground." He also speaks of their 

 perching and roosting on trees.— W. W. Spicer, 

 Potterne, Wilts 



Destruction op Plants by Goats (p. 47). — 

 A most interesting tree, the bottle palm (Hyophorbe 

 Barklyi, Hook, fil.), is fast disappearing under the 

 combined attacks of goats and rabbits. This palm 

 is peculiar to a small island known as Round Island, 

 which forms one of a group distant about twenty 

 miles from Mauritius. It is far from common even 

 in its native home. There are no indigenous mam- 

 mals on the island, but goats and rabbits have been 

 introduced, and these bid fair to destroy this very 

 curious member of the vegetable kingdom, climbing 

 up the trunk — an easy process, as it is of a swollen, 

 gouty form— and nibbling off the shoots. The 

 young plants, as they spring from the ground, have 

 of course no chance against these tiresome marau- 

 ders.— W. W. Spicer, Potterne, Wilts. 



Is THE LANDRAIL A BlRD OF PASSAGE?— In 



the month of August, 1852, I crossed in a steam- 

 boat from Hull to Rotterdam. y.tWhen we were 

 about forty miles from the Brill, a landrail, flying 

 towards Holland, fell on the deck and was caught. 

 The sailors could not resist the temptation of peer- 

 ing at the strange bird, and he having recovered 

 his strength flew from the basket and recommenced 

 his flight to Holland, which no doubt he reached in 

 safety. — T. G. Thompson, Ashdown Park, Sussex. 



Who killed Cock Robin ?— At p. 46 of your 

 February number, it is stated that "Who Killed 

 Cock [poor] Robin was written by the Rev. — 

 Moseley, who is still living." If this be so, he must 

 himself be a hearty old cock. I have the song set 

 to music— I suppose by Dr. Calcott— in the " Ju- 

 venile Amusement" entered at Stationers' Hall, 

 1797. This collection contains most of the old 

 popular ditties, "Who Killed Cock Robin" and the 

 " Multiplication Table " being highly dramatic and 

 clever. If the alleged author be living, and had 

 attained to say 20 or 23 at least, if in Orders 

 when it was written, he must be between 90 and 

 100 at least. The song, however, is not published 

 with the parade and flourish of a new song, and I 

 doubt not might be traced to a much earlier date 

 than 1797— G.B.,Bath. 



Eggs of Lepidoptera. — In Science-Gossip, 

 November, 1870, there appeared some good remarks 

 on "The Eggs of Butterflies and Moths." There 

 is a vast fund of beautyjand interest in them, and as 

 is justly remarked in the paper alluded to, " they 

 are by no means common in cabinets." I have a 

 few, but there is some considerable difficulty, first 

 in finding them, and secondly, in mounting them. 

 I. am sure many with myself would feel very 

 greatly obliged if somf entomologist would inform 

 us where, i. e. on what vegetables and shrubs,_ we 

 are likely to find them, and perhaps some micro- 

 scopist would at the same time state the best 

 medium for preserving them. I am inclined to 

 think one part of glycerine to twelve of distilled 

 water is the best ; if denser than that, they shrivel 

 from exosmose — G. H. B., Galten House, Shanklin. 



Popular Errors.— Can any of your readers 

 assist me in collecting instances of "popular 

 errors," such as— As blind as a mole, As deaf as an 

 adder ? There are a great many ; some are quite 

 local, others extend over the whole of England ; 

 and knowing what a large circulation the Science- 

 Gossip has, I thought that mentioning the subject 

 in its pages would be a good way of obtaining 

 instances which otherwise I should not hear of.— 

 C. K. B. 



