Sbptembee 7, 1900.] 



SCIENCE. 



383 



suspicion of that of the raspberry. Most im- 

 portant is the time of fruiting as regards the 

 future of the plant economically, for it comes 

 into bearing as the raspberries are failing and 

 before the blackberries are ripe. The ' Mahdi ' 

 is very prolific and has considerable claims to 

 be a decorative plant ; it will not, however, be 

 placed upon the market for probably another 

 twelve months at least. 



A SUMMARY of the work done by the Eeichs- 

 anstalt from February, 1899, to February, 

 1900, has been published in the Zeitsehrift fur 

 Insirumentenkunde. According to an abstract 

 in the Electrical World the comparison of the 

 two sets of standard resistance coils showed 

 good agreement ; the variations during seven 

 years amount only to a few hundred thou- 

 sandths of the original value. Preliminary ex- 

 periments were made for determining the capac- 

 ity of an air condenser. A greater number of 

 zinc and cadmium standard cells were made for 

 testing purposes ; renewed measurements gave 

 results in good agreement with the figures pub- 

 lished last year. The exact investigation of 

 the conductivity of aqueous solutions has been 

 concluded for the chlorides and nitrates of 

 alkaline metals. The instruments, storage 

 batteries, primary cells, cut-outs, insulating and 

 conducting materials, arc lamp carbons, fuses 

 which have been tested, are given in a table. 

 Statistical material on the use of electric meters 

 in practice has been collected ; according to the 

 information given by the central stations, about 

 60,000 meters are at present in use in Ger- 

 many, while about twice as many is the num- 

 ber estimated by the manufacturers. The ap- 

 paratus for testing alternating current in- 

 struments was completed. A new resistance 

 material of Heraeus was tested, the'j investiga- 

 tion of the resistance devised by Kundt was 

 continued. One hundred and eleven Clark and 

 22 Weston cells were tested. The variation 

 from the normal e. m. f. was below 0.0003 volt 

 for 83 Clark cells, between 0.0004 and 0.0006 

 volt for 23 cells, 0.001 volt for 1 cell and 

 greater than 0.001 volt for 4 cells. The agree- 

 ment of the commercial Weston cells was 

 found to be very satisfactory. The magnetic 

 properties of 25 samples of steel and iron were 

 tested. An investigation was made of the dif- 



ference between continuous and interrupted 

 magnetization. Also preliminary measure- 

 ments were made to investigate the influence 

 of repeated annealing upon the magnetic prop- 

 erties of diflferent samples of iron. 



Some of our Consuls in South America, says 

 the London Times, refer in their last reports to 

 the virtues ascribed to the tea made from yerba 

 mate, a herb which takes the place to some ex- 

 tent of tea and coffee, and which is derived 

 from the leaves of the Ilex Poraguariensis, a tree 

 of from twelve to twenty feet in height. The 

 Consul in Paraguay says this tea is consumed 

 by a large proportion of the populations of Bra- 

 zil, the Argentine, Uruguay, Chili and Para- 

 guay. The leaves are gathered every two or 

 three years and dried over a slow fire ; they are 

 then pounded in mortars in the ground, and 

 finally packed in fresh skins and dried in the 

 sun. The tea is made by pouring boiling 

 water on the leaves, which serve for several 

 infusions. The taste is bitter, but not unpleas- 

 ant, and the effects are asserted to be invig. 

 orating. It is said that it would be valuable 

 as a restorative to troops on the march and 

 on active service, and the French Govern- 

 ment have ordered a shipment of mate for 

 the colonial troops and some samples have 

 also been sent to Germany for experimental 

 purposes. An attempt is also being made 

 to introduce it into the United States as 

 a suitable beverage for the working classes. 

 When analyzed the tea is shown to contain 

 caffeine and cafetannic acid in important pro- 

 portions. The Council-General at Rio also re- 

 fers to the subject as one of commercial interest. 

 It is claimed, he says, on behalf of the tea that 

 it possesses superior stomachic properties to tea 

 and coffee, in that, while it is refreshing and 

 invigorating and favorable alike to mental and 

 physical exertion, it does not disturb the nerv- 

 ous system. But even Brazilians are not agreed 

 as to its merits, some alleging that by its aid the 

 most arduous work can be done, such as forced 

 marches of troops on short rations ; others as- 

 serting that in war cofifee has proved much 

 more sustaining. However this may be, it is 

 largely consumed in South American countries 

 when the prices of low grade China teas are 

 too high to admit of their shipment to South 



