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THE POPULAR SCIENCE MONTHLY. 



Macmillan will publish in the fall two 

 volumes by Prof. Wyville Thomson, on the 

 "Results of the Challenger Expedition." 

 This work will be illustrated by drawings, 

 made on the spot by Mr. Wild, the artist 

 of the expedition, of the many curious and 

 beautiful creatures now for the first time 

 brought to light. 



A new grape-fungus, which first appears 

 on the leaves of the grape-vine, in the form 

 of a minute yellow spot, was described by 

 Dr. Engelmann, at a recent meeting of the 

 St. Louis Academy of Science. It makes 

 its appearance just before and during the 

 flowering period, as far as known attacking 

 only the leaves, or rarely the petioles and 

 peduncles. It kills the leaves, and thus 

 cripples the plant, and attacks all varieties 

 indiscriminately. 



A set of wheels was lately taken from 

 beneath the baggage-car of the California 

 and Oregon express train at Sacramento, 

 which had traveled in daily use 91,800 

 miles, nor were they worn out even then, 

 but had become loose on the axle. 



The Challenger Expedition returned to 

 England May 23d, after an absence of three 

 years and five months. During that time 

 the vessel sailed 61,840 miles. The number 

 of soundings made was 370, of dredgings, 

 360. Some hundreds of .specimens were 

 sent home during the voyage. The mor- 

 tality was not above the mean, and, when 

 it is remembered that the average time at 

 sea was 220 days per year, it is surprising 

 that the health of those on board (259 in 

 number) was as good as it was. 



During the thirty years, 1841 "70, the 

 death-rate of England and Wales was near- 

 ly stationary, about twenty-two per thou- 

 sand. It must not be supposed, however, 

 that in the mean time no progress was made 

 in sanitary science. The rapid develop- 

 ment of manufactures led to the crowding 

 of people in towns, and this must have 

 tended to produce a higher death-rate. 

 The local statistics strikingly exhibit the 

 influence of thia massing of people in man- 

 ufacturing and mining centres. For in- 

 stance, while Cambridgeshire shows a pro- 

 gressive decline of death-rate, in the West 

 Hilling of Yorkshire, where the urban pop- 

 ulation has been enormously increased, the 

 death-rate has been steadily rising. 



A street-pavement of pig-iron is soon 

 to be tried in Paris. In constructing a 

 roadway of this kind, a bed of mortar is 

 first laid down, which is covered by a strong 

 layer of asphalt; it is in this layer that the 

 iron cakes, which arc about 1.6 inch thick, 

 are set. These cakes, it appears, preserve 

 the homogeneity of the bitumen and pre- 

 vent its depression, ami render the asphalt 



less slippery for horses. This pavement will 

 cost more than the compressed asphalt, but 

 it is estimated that it will save 5u per cent, 

 of the repairing expenses, which are very 

 considerable. The end desired is to avoid, 

 by the adoption of this kind of pavement, 

 the depressions in roads over which a great 

 deal of traffic passes. To attain this, it does 

 not suffice to pour bitumen upon a well- 

 prepared ground lightly covered with a coat 

 of lime ; the resistance of the ground should 

 equal that of an old macadamized bank ; 

 and a very thick bed of mortar, which should 

 be very homogeneous, should be laid before 

 the asphalt. 



A new process of gas-manufacture has 

 been patented by Malam, manager of the 

 Dumfries (Scotland) Gas-Works. The ad- 

 vantage claimed by the inventor for the 

 new process is, that a large proportion of 

 the liquid hydrocarbons, which would other- 

 wise go to form tar, are converted into gas, 

 and thus an increased production of gas is 

 insured to the amount of 3,000 or 4,000 

 feet per ton, while the quality is not de- 

 teriorated. 



In announcing the sale of the Hoosae 

 Tunnel machinery, the Engineering ami 

 Mining Journal remarks: "The contractors 

 completed, in the most satisfactory manner 

 and it is said at a considerable pecuniary 

 sacrifice, a most difficult work (the tunnel), 

 and one which is of considerable advantage 

 to the State (Massachusetts), and it is great- 

 ly to be regretted that the government of a 

 great State should resort to those devices, 

 to avoid the fair and honest performance of 

 their engagements, which, when practised 

 by individuals, are characterized as 'tricky' 

 and ' dishonorable.' " 



Water which has been kept for some 

 time in the state of ebullition does not 

 make so good an infusion of tea as water 

 "just upon the boil." A reason for this is 

 suggested by a writer in the Chemical JVevt, 

 who says that the escape of dissolved gnsi s 

 might possibly account for the inferiority of 

 tea-infusion made with long-boiled water. 

 To test this, he passed for ten minutes 

 through boiling water a stream of carbonic- 

 acid gas, and then made an infusion of tea 

 with it. The result was decidedly better 

 than when water was employed that had 

 boiled for the same length of time without 

 the addition of the C0 2 . 



The depth of the Pacific Ocean between 

 Hawaii and Tahiti, as developed by the 

 soundings of the Challenger Expedition, 

 ranges from 2,000 to 8,000 fathoms, with 

 one exception of 1,525 fathoms. The bot- 

 tom, except near the islands, is mainly red 

 clay, with much oxide of manganese in small 

 concretions and many foraminifers. 



