POPULAR MISCELLANY. 



7 i 7 



Leaf and Stick Insects. The leaf insect 

 and the walking-stick insect are curious creat- 

 ures. All of the family to which they belong 

 are nocturnal in habit, and spend their days 

 resting on trees and bushes the leaves of 

 which form their food. They so resemble 

 the leaves and twigs as to escape all but the 

 very keenest observation. In the leaf in- 

 sect, the head and thorax form a stalk, while 

 the abdomen, which is flat, thin, and much 

 dilated, exactly resembles a leaf. The six 

 legs have broad, membranous appendages on 

 the upper part, which are especially notice- 

 able on the fore-legs ; so that the creature 

 while resting has the appearance of a leaf 

 that has been gnawed on both sides by a cat- 

 erpillar. While the color of the insect va- 

 ries at different periods of its life, it always 

 more or less resembles a leaf at some stage ; 

 when settled on the leaves and eating at 

 them, its body becomes bright green. After 

 death it becomes brown like a dry leaf. The 

 stick insects are common in the tropics, which 

 are the principal habitat of the leaf insects, 

 and are also found in temperate regions, in- 

 cluding the United States. The tropical spe- 

 cies are the largest, some of them reaching 

 nine or ten inches in length. They are 

 hatched from the egg in a form closely re- 

 sembling that of their parents, coming into 

 the world with three pairs of legs, which 

 keep their shape with but little, if any, al- 

 teration during their entire existence, and 

 which are all walking limbs. At all stages 

 of their life they closely resemble sticks and 

 twigs, either green and growing, or brown 

 and withered, from which they obtain their 

 name. They are also called specters, from 

 their skeleton-like appearance and their slow, 

 stealthy movements. A colony of these in- 

 sects in the London Zoological Gardens is 

 breeding prosperously. 



Fort Ancient. Mr. "Warren K. Moore- 

 head gave the American Association an ac- 

 count of his excavations of Fort Ancient, 

 Ohio, and what he found there, in which he 

 more fully elaborated the theory of the his- 

 tory of that work which was indicated in the 

 volume upon it that we have recently re- 

 viewed. One of the points of this theory, 

 based on the comparison of the potteries and 

 implements found in and around the fort, 

 and the burials, was that it was a point of 



contest, or battle-ground, between two races 

 of men. Other questions occupied the au- 

 thor's mind as he considered the subject, 

 and years, he said, might be spent in care- 

 ful excavation of the graves and cemeteries, 

 and there would still remain sufficient ma- 

 terial to engage the attention of antiquaries 

 for a long time to come. " This great in- 

 closure, so rich in facts, so productive of im- 

 plements that tell us of the every-day life of 

 the ancient people who lived within its walls, 

 may yet reveal to the patient investigator a 

 history that shall go far toward dispelling 

 the darkness that surrounds the origin and 

 movements of ancient men on the American 

 continent." The site has been bought by 

 the State of Ohio, and will be preserved as 

 a State park. 



The Spectra of the Metals. A paper by 

 Prof. Rowland, of Johns Hopkins Univer- 

 sity, on The Spectra of the Metals, was re- 

 ceived by the Physical Section of the British 

 Association as a most important advance in 

 our knowledge. The author had undertaken 

 during the past year the measurement of 

 the wave-lengths of the lines of nearly all 

 the metallic spectra, and had compared 

 them with the solar spectrum, in order to 

 ascertain which metals were certainly pres- 

 ent in the sun. The object of the research 

 was primarily to find out what sort of thing3 

 molecules are, and in what way they vibrate. 

 This can be deduced from the wave-lengths 

 of the light emitted if we can find any rela- 

 tion between these wave-lengths. If the 

 molecules are spheres, we should have a 

 series of bands getting gradually nearer 

 together toward the violet, and representing 

 harmonics of one fundamental vibration. A 

 spheroid or ellipsoid would give a similar 

 crowding, but not so uniformly arranged. 

 The author had worked on a larger scalo 

 than in any previous observations, with neg- 

 atives twenty feet long for the whole spec- 

 trum, lie looked for and found many indi- 

 cations of the truth of the periodic law, 

 which points to the fact that similar chemi- 

 cal substances have mohculss vibrating in a 

 similar manner. As examples, nearly every 

 line in the spectrum of zinc has a corre- 

 sponding one in that of cadmium ; so also 

 with calcium, strontium, and barium, and 

 with potassium, caesium, and rubidium. In 



