Di-.sTRii TioN (II- rill-; .\K(;i-:.\ii M-: ant. 5^7 



very tiiu' particles ol' the sul)liinale Hoatinji- about. When the 

 suhhniate lias been sprinkletl on to the soil at any point, it remains 

 -uftieientlv virulent to affect the ants for a long time. Certain 

 ))rotecie(l s])ots treated eight or nine months ago still react on 

 the ants when they wander over them. Heavy rains carry the 

 corrosive sublimate away to a very large extent, but light rains 

 simplv carry it into the soil, and then, as the moisture eva|)orates. 

 there is a tendencv for the corrosive sublimate to be deposited 

 on the surface, thus reproducing " ant-tape " conditions. This 

 suggests that it may be possible to treat the foundations of build- 

 ing's, either during construction or afterwards, with corrosive 

 <ublimate in solution, and fortifv them against ant invasion. 



Geology of South West Africa.— Some months 



ago Trof. S. j. ."^liand. i>f Victoria College, Stellenljosch, visited 

 ."^outh-W'est Africa f<ir the ptirpose of studying the occurrences 

 i>f alkaline rocks in the desert sotith of Likleritz Bay. On 

 arrival there Dr. Shand found that Prof. Erich Kaiser, the dis- 

 tinguished petrologist of Gilssen, was in the country as a 

 ])risoner of war. and had come out from Europe for the express 

 pur])ose of studying those very rocks. Dr. S'hand writes to the 

 Geological Magazine* that Prof. Kaiser has utilised his enforced 

 leisiuT by studyinu- the alkaline rocks most minutely, and map- 

 ping the occurrences on s])ecial, large-scale topographic sheets. 

 I'nder the circumstances Dr. Shand has abandoned his intention 

 i»f writing anything aljout these rocks for the present. In the 

 meantime, he declares that Prof. Kaiser's memoir on the sub- 

 ject, when it appears, will be found to possess a (|uite extra- 

 ordinary interest for petrologists. 



Potash from Seaweed. — A recent issue of Nature. 

 ijuoting from United States publications, refers to the existence 

 I if nearly 400 sf[uare miles of seaweed beds along the United 

 States Pacitic coast. It is officially estimated that these beds 

 can sui)ply 59.000,000 tons of seaweed annually, capable of pro- 

 ducing an aggregate of 2,300,000 tons of potassium chloride, 

 i'he United States Dei)artmcnt of Agriculture is undertaking the 

 experimental ])roducti(>n of potash from this seaweed on a com- 

 mercial scale. An apjM'opriatiou of 175,000 dollars has been 

 made for this purpose, and the plant, which wnll probably be put 

 up in Southern Cali'fornia. will be capable of dealing- with 200 

 tons of wet seaweed ])er da}-, thus producing about five tons of 

 Ijotassium chloride daily. Xumerous experimental methods will 

 be employed, but for the n-iost part distillation processes will be 

 used. 



* (1917). 4 I5J, 235- 



