September 21, 1900.] 



SCIENCE. 



455 



Expedition sent to Nigeria to the effect that all 

 the members are perfectly well, although they 

 have spent four months in districts where ma- 

 laria is specially prevalent and deadly. They 

 have not kept the fever off by the use of quinine, 

 and they attribute their immunity to the care- 

 ful use of mosquito nets at night. Experiments 

 are reported in the Archivio per le Scienze Med- 

 ichi, abstracted in the New York Medical Bee- 

 ord, of an experiment carried out by Eugenio 

 di Mattei on himself and four others. A hut 

 situated in an extremely malarial region, in- 

 fested by mosquitoes, was chosen, and here the 

 five slept for thirty-two nights. Their work 

 during the day was arduous, their food scanty, 

 their accommodations were uncomfortable ; 

 they took no quinine or other medicament, but 

 their hut was so completely protected by wire 

 gauze that no mosquitoes were able to obtain 

 access. No one of the five contracted malaria, 

 although other workmen sleeping in the neigh- 

 borhood and unprotected from the mosquitoes, 

 suffered from grave forms of the disease. 



In 1898 there was mined in the United States 

 somewhat over nineteen million tons of iron 

 ore, which was the largest quantity up to that 

 time ever produced in a single country in a 

 single year. But according to the announce- 

 ment recently made by the U. S. Geological 

 Survey, the production of iron ore in the 

 United States was 24,683,173 tons, an increase 

 of 27 per cent, over 1898. In spite of this large 

 increase the price is about 25 per cent, higher 

 than in 1898. 



Dk. Eeginald a. Fessenden writes as fol- 

 lows to the Electrical World referring to patents 

 by Mr. Tesla which have been widely discussed 

 in the daily press: "With reference to your 

 article on ' Insulation by Freezing, ' in the issue 

 of August 25th, may I be permitted to point out 

 that the patents referred to are invalid, as this 

 method was fully described in my paper on 

 'Insulation and Conduction,' read before the 

 American Institute of Electrical Engineers in 

 1898, and printed in its 'Transactions' (Trans. 

 A. I. E. E., 1898, page 14). The passage is as 

 follows : ' ' The second (plan) occurred to the 

 writer on reading Elihu Thompson's article on 

 the use of liquid air as an insulator. It is this : 



Since ice at only 12 degrees below freezing has 

 a specific resistance of over 1000 megohms, i. e., 

 as good as some brands of insulation, why not 

 make the conductorshollow,lay them in atrench 

 filled with water, pass cold brine through the 

 pipes, use the brine for cooling houses, making 

 ice, etc., and let the frozen water act as the in- 

 sulator. A rough calculation shows that this is 

 commercially feasible, even neglecting all 

 sources of profit from the furnishing of the 

 brine, i. e., if it were used only for cooling 

 the pipes. After making all allowance for 

 friction of fluid, cost of power, etc., the balance 

 comes at the right end, if the line is always 

 fully loaded." This was published more than 

 two years prior to the date of application of 

 said patents, the said date being June 15, 

 1900. 



The report of the Principal Chemist of the 

 Government Laboratory of Great Britain upon 

 the work of the laboratory for the year ended 

 March 31st last has been issued as a Parliamen- 

 tary paper. According to an abstract in the Lon- 

 don Times it appears that in the Customs Depart- 

 ment during the past year, 226 samples of tea, 

 representing 3322 packages, were found to con- 

 tain exhausted leaves, or to be mixed with sand 

 or other substances within the meaning of the 

 Act, and were therefore refused admission for 

 home consumption. Of these 3322 packages, 

 2274 were exported and 1048 destroyed. Eight 

 thousand four hundred and eighteen samples 

 of tobacco, tea, coffee, soaps, drugs, varnishes, 

 etc., were examined during the 12 months; 

 167,080 samples of beer, spirits and wines were 

 examined in the same period. The number of 

 analyses and examinations made in the Excise 

 branch amounted to 68,287, or 1864 more than 

 in the preceding year. Seven thousand five 

 hundred and two samples of wort in various 

 stages of fermentation had been examined to 

 check the declaration of gravity made by the 

 brewer. In 614, or rather more than 8 per 

 cent, of these cases, the original gravity was 

 found one degree or more above that declared 

 by the trader or found by the officer. In 583 

 cases the increased gravity was less than five 

 degrees, in 26 cases five degrees and less than 

 ten, and in five cases ten degrees and upwards. 

 Two thousand three hundred and eighty-six 



