PROCiEEDINGS OF THE POLYTECHNIC ASSOCIATION. 457 



nesium wire for the produ'etion of light in the interior by whicli to plioto- 

 graph the mysterious inner chamber and coffer. 



Anthracite for Locomotives. 



On the Pennsylvania and Heading Railroad a great number of experi- 

 ments prove that a locomotive drawing an average train of six cars, weight 

 80 tons, over a road 95 miles long, having an average grade of 6.16 feet 

 per mile, at an average speed of nearly 26 niiles an hour, will consume in 

 the trip only 23 lbs. per mile of anthracite coal. Twenty-two stoppages 

 were made in each trip, with the " exhaust" and " throttle" wide open ; 

 the speed of the engine being regulated by the reverse lever. By slight 

 modifications almost any engine can be made into a coal-burner, and thus 

 the smoke nuisance can be entirely abated. 



Mr. E, Stevens said the higli price of coal at the present time has driven 

 railroad companies in New England to the use of wood. The census 

 reports show a large increase in the amount of wood grown in Xew England. 



The selected subjects were then taken up. 



The Manufacture of Bisulphide of Carbon. 



Dr. Parmelee stated that about 850.000 worth of bisulphide of carbon ia 

 used annually in the United States. It is a powerful solvent of India rub- 

 ber and other gums, and being very volatile, is easily removed from the 

 solution. It is remarkably transparent, and has extraordinary powers of 

 refracting light; these two properties have recommended its use for lenses 

 in optical instruments. 



It is a chemical compound of carbon and sulphur, in the proportion of 

 two equivalents of sulphur to one of carbon, C Ss, which is in the propor- 

 tion of 6 pounds of carbon to 32 of sulphur ; the atomic weight of carbon 

 being 6 and of sulphur 16. To effect the combination it is only necessary 

 to bring the two elements in contact at a bright red heat, the atmospheric 

 air and other matters being excluded. Charcoal is heated in a close vessel, 

 and brimstone in small lumps is dropped in upon it. The sulphur is evapo- 

 rated, and as the vapor comes in contact with the incandescent coal, 

 chemical combination takes place in the proportion stated. 



As the bisulphide of carbon boils at 110°, it is of course in the state of 

 vap(jr in the heated vessel where it is formed, but it' is reduced to tlie liquid 

 state by passHig it through c<jndensers. When first formed it is mingled 

 with the vapor of sulphur and with sulphuretted hydrogen, but may be 

 purified from these. 



Tiie .speaker then made drawings on the blackboard of the apparatus 

 which he had employed on a large scale in manufacturing the bisulphide 

 of carbon, but these could be reproduced only by elaborate engravings. 



Manufacture of Chloroform. 



The Chairman gave a short description of the mode of making chloroform, 

 and stated that he was pleased to learn thatthe first that was ever pro- 

 duced in the world was made in this country, thus completing our claim to 

 the discovery of anaesthesia — the greatest discovery in medicine that has 

 ever been made. It iti admitted that nitrous oxide and ether were first 



