MISCELLANY. 



6 35 



A Spider's Engineering. A writer in 

 Hardmicke's Science- Gossip saw a spider's 

 web stretched across a small mill-stream, 

 and attached on either side to stems of 

 grass and other herbage. The stream was 

 about three feet in width, and the web re- 

 sembled a cart-wheel in general outline, 

 having a diameter of at least six feet. The 

 writer asks how "an animal that neither 

 flies, leaps, nor swims," could accomplish 

 such an engineering feat. But is it true 

 that the spider does not swim or leap ? In 

 fact, the animal can run on the surface of 

 water, can leap from place to place, and can 

 float after the manner of Mr. Home the 

 medium. It can even dive in water. But, 

 further, it can swing like a pendulum, 

 suspending itself like a thread from some 

 elevated point. The writer in Hardwicke 

 does not tell whether there was any object 

 near the web on either margin of the stream 

 of sufficient height to allow of the animal's 

 so swinging from one side to the other. 



Geology of the Great Plain of Morocco. 



The Journal of the Geographical Society 

 (British) has a paper by George Man, F. G. 

 S., on the geology of Morocco, of which we 

 give the substance. The plain of Morocco 

 rises 1,700 feet above the sea-level, and is 

 covered with a tufaceous crust, from a few 

 inches to three feet thick, which is burnt 

 for lime near the city of Morocco. The 

 underlying rock is of similar composition 

 but not so hard, and is called by Mr. Man a 

 " cream-colored limestone and gray marl of 

 cretaceous or tertiary age." Midway be- 

 tween Mogador and Morocco are flat-topped 

 hills 200 or 300 feet high, covered with 

 tabular masses of chalcedony. This sug- 

 gests an enormous erosion of the plain. 

 The author contradicts Rolfe and others 

 who assert that snow remains upon Mount 

 Atlas during the entire year, and says that 

 in the first week of May snow was to be 

 found only in deep gullies and in drifts. 

 The mass of the Atlas rauge is mainly com- 

 posed of porphyrites and porphyritic tufas, 

 overlaid by cretaceous rocks, with basalts 

 rising in erupted dikes and masses evident- 

 ly post-cretaceous. Metamorphic rocks ap- 

 pear in rugged hills near Morocco, and 

 white limestone on the high Atlas. Glacial 

 moraines may be seen on this range nearly 



8,000 feet above the sea, forming gigantic 

 ridges and mounds of porphyritic blocks, 

 in some places damming up the ravines; 

 and at the foot of Atlas are enormous 

 inound3 of bowlders. These mounds often- 

 times rise 2,000 feet above the level of the 

 plain, and according to Mr. Man were pro- 

 duced by glaciers. Of marine drift no trace 

 is visible. 



Cross between the Zebu and European 

 Cattle. The organ of the Royal Prussian 

 Agricultural Department contains a notice 

 of some experiments on the cross between 

 the zebu, or Indian ox {Bos Indicus), and 

 European cattle, by W. Nathusius-Konigs- 

 born. The doubts that have existed in re- 

 gard to the fecundity of this cross led to 

 the experiments which, the writer thinks, 

 must forever set the question at rest. The 

 male zebu made use of was a yearling calf 

 from the Zoological Gardens, of the peculiar 

 bluish-white color characteristic of the zebu 

 race. Four heifers of Holland stock were 

 got with calf by this animal, and produced 

 two heifers and two bull-calves, all of which 

 were successfully raised. Though the dams 

 were variously colored, all the calves had 

 white stars in their foreheads. When they 

 arrived at suitable age, they were bred with 

 each other and with other cattle, and both 

 sexes proved in every respect capable of 

 propagating their race. The amount of 

 milk given by the half-bloods was about 500 

 quarts per annum. This was so much below 

 the ordinary average as to prevent all hope 

 of their being a desirable breed. In addi- 

 tion, the oxen, from which much was ex- 

 pected in speed and endurance, proved so 

 incorrigibly obstinate as to defy all efforts 

 to train them for the yoke, lying down on 

 the smallest provocation, and in one case, 

 where it was necessary to lead one of them 

 a short distance, the animal died the next 

 day, it was supposed from the effects of 

 anger and excitement. They acted much 

 more like half-tamed wild-beasts than like 

 domestic cattle. The only redeeming feat- 

 ure was the quality of their flesh, which, in 

 those that were sent to the butcher, proved 

 to be excellent. 



Solidifying Petroleum. The Journal dt 

 VEclairage au Gaz describes as follows a 



