SCIENCE. 



[Vol. XIV. No. 352 



protecting each hill by a piece of plant-cloth or cheese-cloth 

 about two feet square. This may be done simply by placing it 

 over the plants, and fastening the edges down by small stones or 

 loose earth. It is better, however, to hold it up by means of a half 

 barrel- hoop or a wire bent in the form of a croquet arch. 



— Since the Johns Hopkins Hospital was opened, the Ti?nes re- 

 ports that over 400 patients have been received. It now contains 

 109. The training-school for nurses is making good progress. 

 Arrangements are being made to publish regularly the discoveries 

 and observations of the experts of the hospital. This publication 

 department is expected to be of value to medical literature. The 

 Bulletin will be issued monthly, and will correspond with the Cir- 

 ctdar of the university, but other more important papers will be 

 added from time to time. In the Bulletin will be the proceedings 

 of the newly organized medical society. This society is modelled 

 on the plan of the one connected with the Charite of Berlin ; and 

 its object is to bring the men connected with the hospital into 

 closer connection, to stimulate research, and to protect the claims 

 of priority of work done by the members. Dr. Welch is the presi- 

 dent, and Dr. Robb is the secretary. 



— A new soft alloy, which adheres so firmly to metallic, glass, 

 and porcelain surfaces that it can be used as a solder, and which, 

 in fact, is invaluable when the articles to be soldered are of such a 

 nature that they cannot bear a high degree of temperature, consists 

 of finely pulverized copper dust, which is obtained, according to 

 Iron, by shaking a solution of sulphate of copper with granulated 

 zinc. The temperature of the solution rises considerably, and the 

 metallic copper is precipitated in the form of a brownish powder ; 

 twenty, thirty, or thirty-six parts of this copper dust, according to 

 the hardness desired, being placed in a cast-iron or porcelain-lined 

 mortar and well mixed with some sulphuric acid, having a specific 

 gravity of 1.85. To the paste thus formed are added seventy parts 

 by weight of mercury, with constant stirring ; and, when thus 

 thoroughly mixed, the amalgam is well rained in warm water to 

 remove the acid, and then set aside to cool. In ten or twelve hours 

 it is hard enough to scratch tin. On being used, it is heated to a 

 temperature of 375" C, and, when kneaded in an iron mortar, be- 

 comes as soft as wax. In this ductile state it can be spread upon 

 any surface, to which, as it cools and hardens, it adheres with great 

 tenacity. 



— Professor Arthur Winslow, who was lately elected State 

 geologist of Missouri, has established his headquarters at the State 

 capitol. The State appropriated |)2o,ooo for the maintenance of a 

 geological bureau during the years 1889-90. In 1873-74 Professor 

 Broadhead^ade a partial survey of some portions of the State, but 

 for lack of funds was unable to continue the same. The United 

 States Topographic Survey covers the counties of Jasper, Barton, 

 Vernon, Bates, Cass, Jackson, Clay, Platte, Ray, Lafayette, John- 

 son, Henry, St. Clair, Cedar, Dade, Lawrence, Greene, Polk, Hick- 

 ory, Benton, Peltis, Saline, Carroll, Howard, Cooper, Morgan, 

 Camden, Miller, Cole, Moniteau, Boone and parts of Monroe, 

 Audrain, Pike, Montgomery, Callaway, and St. Louis. This is but 

 a fraction of the mineral-bearing lands of Missouri. The director 

 of the United States survey has notified Professor Winslow that 

 the government will co-operate with the State, and will put a full 

 corps of surveyors in the field next spring, who will work in such 

 localities as the State geologist may direct. Professor Walter P. 

 Jenney has been assigned work in surveying the lead and zinc de- 

 posits. James D. Robertson of Washington University, St. Louis, 

 has been appointed assistant to State geologist ; Dr. Hambach of 

 Washington University, St. Louis, assistant paleontologist for the 

 State ; Elston Lonsdale of Columbia, aid to paleontologist ; Leo 

 Gluck of Lamonte, aide and mining engineer. Professors Jenney 

 and Robertson have been assigned work at Joplin, and they will 

 perform co-operative work in regard to the lead and zinc deposits 

 of that locality, and, when completed, extend eastward. Professor 

 Lonsdale has been directed to collect material from the vicinity 

 of Columbia. Leo Gluck has been assigned to the coal-fields. 

 His first work will be in Pettis, Johnson, Lafayette, and Bates 

 Counties. Professor Winslow will first take up the lead and zinc 

 deposits, detail examination of coal-fields, study of building-stone, 

 clays, and sands of the State respectively. The coal-fields of the 



South-west will receive attention prior to other localities, on account 

 df their magnitude. An investigation of the lead and zinc fields- 

 will commence first at Joplin, and extend to Springfield, and from- 

 thence to Franklin County. Building-stone, clay, and sand will be 

 examined from all parts of the State, and tests of the quality and 

 durability made. Regarding the local reports from Ripley, Madi- 

 son, and other South-east counties, of the discovery of gold and 

 silver ore in paying quantities. Professor Winslow says that he has 

 no official information regarding the same. He says that there is 

 silver in South-east Missouri, but whether or not it can be found ia 

 paying quantities he is not able to say. 



— James Prescott Joule, one of the discoverers of the mechanical 

 equivalent of heat, died at his home in Sale, near Manchester, 

 England, on the nth of October, after many years of feeble health. 

 Dr. Joule was born at Salford, Dec. 24, 1818. In his early days 

 he studied chemistry under Dalton. In 1841 and 1842 he worked 

 on the subject which made his name known among physicists, and 

 in 1843, at the Cork meeting of the British Association, published 

 the results in a paper entitled " The Calorific Effects of Magneto- 

 Electricity, and on the Mechanical Value of Heat." For the ex- 

 perimental proof contained in this paper of a definite quantitative 

 relation between heat and work, Dr. Joule was honored by the 

 presentation of medals by the Royal Society, the English Society 

 of Arts, and others. He was the author of a large number of 

 papers, which have been published in collected form by the 

 Physical Society. 



— Garden and Forest states that President Horace Davis, of the 

 University of California, recently received an inquiry from Algeria 

 concerning experience on the Pacific coast with grasses for restrain- 

 ing drifting sands. As much of this kind of work has been done 

 at Golden Gate Park, in San Francisco, the experience of Mr. John 

 McLaren, the efficient superintendent of the park, was asked, and 

 his statement has been forwarded to the distant applicant. Part of 

 the information given by Mr. McLaren is quoted as follows in the 

 Pacific Rural Press : " The grasses found most successful here 

 are the Sea Bent grass (Calamagrostis arenaria) and the Berrnuda 

 grass (Cynodoti dactyloti), both of which have been entirely suc- 

 cessful in holding the loose sand. I would plant the Sea Bent in 

 the most exposed places, and the Bermuda on the protected slopes. 

 We plant in rows one and one-half to two feet apart and one foot 

 deep. Where practicable, the plough is used, dropping the roots 

 in each alternate furrow. Where the dunes are too steep for 

 ploughing, pits are dug with the spade, and, after planting, the 

 sand is trodden firmly with the foot. The plantations have to be 

 examined after heavy wind-storms to replant any roots exposed by 

 the wind. If seeds only can be procured, I would suggest that 

 they be sown in nursery rows, and the plants set out the following 

 season." Of course, there are also many shrubs used, and the 

 nursery at the park has propagated a vast number of the Leptosper- 

 mum and other shrubs which have been found serviceable. 



— It has always been the desire of engineers to obtain " black "" 

 prints from plans and drawings, in place of the present blue-prints. 

 The discovery of a new substance by a French chemist, M. Pe- 

 chard, announced in Iron, may make such a result possible. It is 

 a mixed acid derived from oxalic and molybdic acids, and is there- 

 fore termed " oxalomolybdic acid." The crystals of oxalomolybdic 

 acid, when dry, may be preserved unchanged, either in sunshine or 

 in the dark ; but if moist they quickly become colored blue when 

 exposed to the sun's rays. If characters be written on paper with 

 the solution, they remain invisible in a weak light; but, when ex- 

 posed to sunshine, they rapidly become visible, turning to a deeper 

 indigo-color. It is curious that this effect only happens when the 

 solution is spread over paper or other surfaces ; for the solution 

 itself may be kept unaltered in the bottle for any length of time,- 

 except for a trace of blue at the edge of the meniscus, where by 

 surface action a little is spread against the interior glass walls. If 

 a sheet of paper be immersed in a saturated solution of the acid, 

 dried in the dark, and then exposed behind an ordinary photo- 

 graphic negative, a very sharp print in blue may be obtained by 

 exposure to sunlight for about ten minutes. The color instantly 

 disappears in contact with water ; so that, if a piece of this sensi- 

 tized paper be wholly exposed to sunlight, one may write in white 



