April, 1904.] 



KNOWLEDGE .^ SCIENTIFIC NEWS. 



3D 



process extends completely over the insect, and is drawn 

 upwards to a point. In fact, it is an exact imitation of a 

 sharp vegetable thorn, from which it is indistinguishable. 

 Thus, the Umboiiiii lias merely to crouch down upon a 

 thorny twig and withdraw its legs beneath the shieUl- 

 like pronotum to be completely hidden. 



The above examples include some of the more striking 

 instances of protective resemblance, both general and 

 special. They must not, however, be regarded as even 

 typically exhaustive, for sticks, leaves, .mosses, and 

 lichens, though common patterns, are by no means the 

 only objects copied in insect colour and form, blowers, 

 seed pods or seeds, patches of mould or decay — even the 

 droppings of animals and birds are all prototypes for 

 insect disguise. Moreover, the modilications of form and 

 the varieties of colour and marking which ha\e been 

 called into being by the need for protection are too 



Umbonia spinosa. Bra/il. (.Middle "thorn" on upper part of Stoiii). 



numerous even to tabulate. In the course of his investi- 

 gations, every observant student will constantly have new 

 and striking instances brought to his notice, even though he 

 may never wander beyond the confines of his own county. 

 But it should be recollected that to form a true esti- 

 mate of the protective value of an insect's colour and 

 form, it is absolutely essential to study them in relation to 

 their habitual surroundings; for, as a rule, it is<iuite im- 

 possible to tell from a casual examination whether a 

 special appearance is protective or not. A butterfly in a 

 cabinet drawer is merely a scientific specimen. Its colours 

 may be bright and beautiful, dull and unattractive, as the 

 case may be ; but suspended above a surface of white 

 paper, they have no special significance. On the other 

 hand, when the insect is alive and among its natural sur- 

 roundings, its colour and shape are often seen to have a 

 direct bearing upon its well-being. Thus the study of 

 living specimens cannot be too strongly urged upon the 

 student — not of entomology alone, but of every branch of 

 natural history. 



^^^^^^ 



A RATHER unexpected geographical discovery has been made by M 

 Gabriel Marcel, who in a Paris shop found an Eighteenth Century 

 map on which is shown the project put forward by M. de la Bastide 

 for a canal across the .\merican isthmus by the Nicaragua route. 

 The map. which is finely e.xecuted, is printed on silk, and from its 

 shape was clearly intended for the decoration of a fan. It shows 

 three ships in sail on the Lake of Nicaragua, and marks the 

 suggested route to the west of the lake Though M de la Hastide's 

 project is a matter of geographical history — he wrote a memoir on 

 it in 1791 — the map's existence had been hitherto unsuspected. His 

 was a plausible project, but he did not by any means realise its 

 difficulties, for he was a theorist who never visited the spot, and 

 who depended on the very inaccurate maps of other people 



Professor 

 Adam Sedgwick. 



The Man and his Work. 



When, just over 30 years ago, at a meeting lieUl in the 

 Senate House, Cambridge, the idea was first mooted of 

 a memorial to Professor Adam Sedgwick, if was said of 

 him in the words of Shakespeare, " His life was gentle; 

 and the elements so mixed in liim that Nature might 

 stand up and say to all the world. This was a man." 



It is well at this moment, wlien the Sedgwick Musemn 

 is an actual connnemoration, to recall the up-bringing 

 and achievements of the subject of this splendid allusion. 



The son of a Yorkshire clergyman, Sedgwick', at tiie 

 close of his early education, proceeded to Trmity College, 

 Cambridge, duly took a degree, and was classed as 5th 

 Wrangler. In 1810 he was made a Fellow of his College, 

 and engaged in teaching; and in 1 81 6 was ordained. Hut 

 it was not as a divine that his repute became established, 

 but as a leader in British geology, a soldier in the early 

 campaigns of the science. Klected Woodwardian Pro- 

 fessor of Geology in iSiS, although knowing, we are told, 

 . omparatively little of the study he was to teach, it 

 seemed as if he was predestined for its successlul pro- 

 secution, and it was not long before he stepped into 

 the front rank as an original iiuestigator. His lectures, 

 which formed a novel feature when he entered up(}n 

 the duties connected with tiie Woodwardian Chair, at- 

 tracted general attention, while at the same time the 

 Professor lost no opportunity of promoting and en- 

 couraging the extension of natural science teaching in 

 the curriculum of university studies. Those were early 

 days in geology — in fact, the long-clothes stage and the 

 authorities looked askant at the iconoclastic science, 

 mindful, too, of what it might bring in its train. Un- 

 doubtedly, in the case of many other men, efforts to 

 obtain the recognition of geological and allied studies 

 would ha\e been foredoomed to failure in the face of 

 the frowning repressiveness which prevailed at Cam- 

 bridge. But Sedgwick was endowed with special quali- 

 ties for the task in hand, and never deviated from the 

 chosen path. Moreover, his charming personality and 

 adornments of character disarmed permanent opposi- 

 tion. Of these characteristics there is ample testimony 

 in the opinions (jf his contemporaries. Three prominent 

 hopes possessed his heart in the earliest years of the 

 Professorship, in his own words expressed thus : — 

 " First, that 1 might be enabled to l)riiig together a 

 collection worthy of the University, and ilfustrative of 

 all the departments of the science it was my duty to 

 teach ; secondly, that a Geological Museum might be 

 built by the University, amply capable of containing its 

 future collections ; and, lastly, that I might bring to- 

 gether a class of students who would listen to my teach- 

 ing, support me by their sympatliy, and help me by 

 the labour of their hands." The fulfilment of these 

 hopes is, of course, a matter of history. 



Sedgwick was the author of a lengthy series of papers 

 in British geology, but he wrote no separate woriv. In 

 particular is he known for his elucidation of the Pala;o- 

 zoic system, in which he collaborated with Murchison. 

 He investigated the Magnesian Limestone of the North 

 of iMigland, and the geology of Wales engaged his 

 earnest and successful study. He was elected a Fellow 

 of the Royal Society in 1821, and in 1863 was awarded 

 the envied Copley medal -a year previous to the award 



