Septeiebee 20, 1895.] 



SGIENGK 



375 



ative eye. But even the secondary and 

 earlier grades cannot much longer deprive 

 their pupils of this best fruit of geographic 

 study." 



TIDAL STREAMS ABOUT THE BRITISH ISLES. 



Two small folios of tidal stream charts, 

 one for the North Sea, the other for the 

 west coast of Scotland, have recently been 

 prepared from official material by F. H. 

 Collins (London, Potter, 1894, five shillings 

 each). Each folio contains twelve charts 

 for successive tidal hours. In several local- 

 ities, as the Strait of Dover and the Frith 

 of Clyde, the opposite movement of the 

 tidal currents is shown within moderate 

 distances ; thus exhibiting nicely the origin 

 of the currents in the orbital motion of the 

 water within the tidal wave. The continu- 

 ance of flood tide after high water, and of 

 ebb tide after low water, commonly ob- 

 served in straits and estuaries, and puzzling 

 to many vacation observers, is thus simply 

 explained. A series of similar tidal charts 

 for our Atlantic sounds and bays would be 

 an interesting product of our Coast Survey 

 office. 



METEOROLOGICAL CHARTS OF THE RED SEA. 



This atlas contains twenty-four charts, 

 showing chiefly the winds and the currents 

 for every month. They have been prepared 

 by C. A. Baillie, Marine Superintendent of 

 the (London) Meteorological Office (Lon- 

 don, Eyre and Spottiswood, 1895; 21 shill- 

 ings). The chai'ts of the winds are based 

 on 75,000 observations, mostly along the 

 axial line of the sea. The wind roses ex- 

 hibit both frequency and force. From June 

 to September northwesterly winds prevail 

 over all the Eed Sea, with southwesterly 

 winds east of the entrance strait; from Oc- 

 tober to January there are northerly winds 

 over the northern half, and southerly over 

 the southern half; from February to May 

 the northerlies gain on the southerlies, and 



return to summer conditions. The surface 

 currents are irregular, fluctuating with the 

 winds. This is especially marked at the 

 strait, where no persistent surface inflow is 

 indicated, to compensate the deep outflow 

 that has been described as a steady current 

 and ascribed to the excessive salinity of 

 the sea. W. M. Davis. 



Haevaed University. 



PRELININARY NOTE ON A CONTAGIOUS 

 INSECT DISEASE. 



Since the establishment, July 1st, at the 

 Illinois State Laboratory of ]S"atural His- 

 tory, of a distinct department for the con- 

 tinuous investigation of the contagious dis- 

 eases of insects, this work, in which Mr. B. 

 M. Duggar is immediately engaged, has 

 taken two principal directions. 



In the first place Sporotrichum globuliferum 

 Speg., well known as the fungus of the white 

 muscardine of the chinch bug and of many 

 other insects, was studied cecologically, 

 especially with reference to the effect of ex- 

 posure of the fungus in its various stages of 

 germination, gi-owth and fruiting for various 

 lengths of time, to a graduated series of 

 temperatures. The troublesome liability of 

 this species to arrest of growth or to com- 

 plete destruction by drouth, by heat and by 

 cold, together with the fondness which cer- 

 tain prolific field mites have shown for it as 

 an article of food, has led us to search dili- 

 gently for a bacterial insect disease, presum- 

 ably less susceptible to these conditions than 

 the muscardines. 



Such a disease Mr. Duggar has been for- 

 tunate enough to find among a lot of squash 

 bugs (Anasa tristis) brought into the labor- 

 atory for experimental uses. It has now 

 been cleai-ly shown that this disease is due 

 to a motile bacillus larger than B. insedorum 

 Burrill, and of different form, preferably 

 aerobic in habit, but capable, nevertheless, 

 of growing beneath the surface of agar, 

 where the colonies are commonly oval or 



