42 



POPULAR SOIEITCE IsTEWS. 



[March, 1889. 



covering the bottoms of vessels and roofs, and 

 for all positions exposed to the action of air or 

 water, it is invaluable, and for purposes 

 where its softness is objectionable, it can be 

 alloyed with tin, to form the hard but readily 

 fusible bronze, or with zinc, to form brass, 

 with its beautiful golden color and innumera- 

 ble uses. 



Copper has a high electrical conductivity, 

 being practically the same as silver, which is 

 the best conductor of electricity known. Rep- 

 resenting the conductivity of silver by lOO, 

 copper would be 99-9, and iron 16.8. This 

 property renders it invaluable in electrical 

 work, and copper wire is largely used in the 

 manufacture of telephones, telegraphic instru- 

 ments, and electric lighting apparatus. 



Copper is one of the few metals having a 

 distinct color, in this respect resembling gold. 

 When rubbed with the hand it also gives off 

 a peculiar and disagreeable odor. It is very 

 malleable, and is readily worked by tlie ham- 

 mer, but is not so duc- 

 tile as iron and not so 

 easily drawn into fine 

 wire. It is also very 

 sonorous, and is one 

 the chief ingredient 

 in the composition i> 

 bell metals. 



The ores of thi- 

 metal occur abundan' 

 ly, the principal or 

 being copper pyritt 

 a double sulphide o 

 copper and iron. In 

 a few localities, notab- 

 ly in Michigan, nativ 

 or metallic copper oc 

 curs abundantly anc 

 can be separated fron 

 the accompanyin< 

 rock, or gangue, by 



a simple process of fusion. The Mich- 

 igan mines produce a large proportion 

 of the copper consumed in this country, and 

 have proved a source of great wealth to their 

 owners. Other less important ores of copper 

 are gray copper, a mixture of sulphur, copper, 

 iron, antimony, arsenic, and occasionally- 

 other metals, and cuprite or oxide of copper. 

 Malachite is a beautiful green mineral con- 

 sisting of a mixture of carbonate and hydrate of | 

 copper, while the magnificent blue azurite con- 

 tains the same salts in different proportions. 



The reduction of copper pj'rites to the me- 

 tallic state, is a very long and complicated 

 process. It goes through several roastings 

 and meltings to drive oft' the sulphur, iron and 

 other impurities, and is finally melted under a 

 layer of charcoal and stirred with poles of 

 green wood, the gases from which reduce the 

 last traces of oxide to the metallic state, form- 

 ing the red, soft, and ductile copper of com- 

 merce. 



Chemically, copper is closely allied to mer- 

 cury ; it forms two sets of compound — cuprous 

 and cupric, the corresponding oxides of which 

 aie bright red and black. The most common 

 salt is the sulphate, or blue vitriol, which is 

 used extensively in the arts for electrotyping, 

 dyeing, and the manufacture of colors. The 

 well-known Paris green is an arsenite of cop- 

 per, and many other green pigments have the 

 metal for their base. 



The salts of copper are, to a greater or less 

 extent, poisonous, and when vessels for cook- 

 ing are made from it, there is great danger of 

 the formation of a basic carbonate of copper 

 cominonly known as verdigris. This is very 

 injurious, and great care should be taken to 

 keep all copper or brass utensils perfectly 

 clean and bright. Pickles are sometimes pur- 

 posely made in a copper kettle to give them 

 a bright green color, but they are thereby ren- 

 dered unwholesome, and such a practice should 

 always be avoided. 



Copper very rarely occurs in living organ- 

 isms, but the brilliant red plumage of a typical 

 bird known as the touraco, or plantain-eater, 

 has been found to contain nearly six per cent, 

 of the metal, and it has also been found in the 

 blood of the cuttle-fish in the form of ha;mo- 

 cyanin, which is blue in its oxidized condition 

 in arterial blood, but colorless in the venous 

 blood. 



When ammonia is added to a solution con- 

 taining copper, a complex double salt is 

 formed of an intensely blue color. This salt 

 is peculiar in that it has the property of dis- 

 solving cellulose, such as paper, cloth, woody 

 fibre, etc. The formation of this blue color 

 is the best chemical test for the presence of 

 copper, being more delicate than another test 

 of immersing a piece of polished iron, such as a 

 needle, in the solution, which reduces the 

 salts of copper to the metallic state, and soon 

 becomes covered with the cliaracteristic red 

 coating. 



A SIMPLE PANTOGRAPH. 



The accompanying engraving (from La 

 Nature) illustrates a cheap and simple pan- 

 tograph by which any drawing ma}- be repro- 

 duced on an enlarged scale. It consists of a 

 flat ring, which can be cut out of a piece of 

 tin or sheet iron. Three holes arc punched 

 through it at equal distances. A small point 

 projecting inwardly is also attached to it. 

 A short piece of elastic cord is passed through 

 the holes and the instrument is complete. 



To use the pantograph, one end of the rub- 

 ber cord is attached to a pin or tack driven 

 into the desk, and the other to a pencil. The 

 drawing to be copied is then placed so that 

 the left hand side shall come under the point 

 in the ring. Then, taking the pencil in the 

 right hand, it is moved over the paper in such 

 a inanner that the point attached to the ring 

 shall follow the outline of the original draw- 

 ing. By this means the pencil traces an en- 

 larged copy on the paper placed underneath 

 it, while the attention 

 )ft he copyist is given 

 nainly to the original 

 rawing and the 

 oint moving over it. 

 should be noted 

 Kit the engraving is 

 icorrect in showing 

 !e left hand asguid- 

 iig the ring. It 

 should be left entirely 

 free, and guided only 

 \ the hand holding 

 le pencil. The elas- 

 tic cord also will 

 necessarily always 

 he straight instead 

 i)f bent at an angle 

 s shown. 

 Sfci-d With a little prac- 

 tice this device mav 

 be made to give verj' satisfactory results. We 

 have found an ordinary key ring to answer 

 very well, the point of metal or cardboard be- 

 ing pressed in between the sides and held in 

 place by their elasticity. In this case the cord 

 must be cut in two and tied to opposite sides 

 of the ring, but the only disadvantage is that 

 the distance between the ring and pencil, 

 upon which the scale of the enlargement de- 

 pends, cannot be varied as easily, as when a 

 a single piece of cord is passed through the 

 holes in the circumference of a flat ring. 



[Original in the Popular Science Netcs.] 



NOTES ON POLLENS AND FERTILIZATION 

 OF FLOWERS. 



BY S. F. LANDRY, M. D. 

 POLLENS REABSORBED BY THE STAMENS. 



Pollens do not always fulfill their mission of fer- 

 tilizing the ovules of the ovary. In a close micro- 

 scopical examination of Oralis rosea, var. Harvei, 

 Oct. 26, 1882, I observed that some pollens had 

 lodged on and among the glands of the stamens, 



