258 



SCIENCE. 



[Vol. XIV. No 349 



INDUSTRIAL NOTES. 

 Electric Blasting Battery. 



The small dynamo-electric machine shown in the accompanying 

 illustrations is intended for use in exploding blasts in mining and 

 similar operations. It is called the " Crescent " battery, and is 

 manufactured by the IngersoU-Sergeant Rock Drill Company of 

 this city. It is said to be the only electric blasting-machine which 

 discharges a uniform current of electricity at every operation, no 

 matter who may use it. Its action does not depend upon the skill 

 of the operator, and, what is very important, there are no parts 

 liable to break or get out of order. 



The following is a description of the machine : A strong steel- 

 wire spring is fixed to a shaft which carries a racked segment. 

 The operator, when he presses the lever over, simply tightens the 

 spring, and at a certain fixed point the lever is automatically re- 

 leased from its contact with the shaft, and the recoil of the spring 

 gives a rapid and uniform movement to the armature, which gener- 

 ates the current. A nut is provided for giving greater or less ten- 



motor is used, and it does its work without a hitch. It is a small 

 arrangement, and is stowed away under the seat in the stern, where 

 it is entirely out of the way. Two hundred and forty revolutions 

 per minute are made by the screw, which gives the boat a speed of 

 about five miles an hour. The boat being a very wide one, this is 

 a very good result. There is no puffing little engine, as in a steam- 

 yacht, heating up the little craft to an uncomfortable degree, re- 

 quiring the constant attention of the engineer in shovelling coal 

 and watching the steam-gauge, and rendering the boat top-heavy 

 by the weight of the boiler. The batteries are directly over the 

 keel, taking up no room which is needed, as their wood -casing 

 makes good seats ; and, as they weigh nearly five hundred pounds, 

 they make excellent ballast. 



The master of the craft moves a little lever, which starts the 

 motor, and then, seating himself directly over it, he has nothing 

 further to do but steer the boat. The batteries take about eight 

 hours to discharge, and the motor will run that length of time 

 without a particle of attention. The motor makes no jar in the 

 boat, as an engine always does on a small boat, and the only noise 



ELECTRIC BLASTING BATTERY. 



■sion to the spring, thus adjusting the capacity pf the battery. The 

 spring never breaks. 



Those who are familiar with electric blasting will not fail to 

 appreciate the' great importance of a uniform discharge. Missfires 

 and serious accidents are often due directly to a lack of uniform 

 strength in the battery-current : one hole will fire while another in 

 the same circuit will miss. With the Crescent, it is claimed that 

 one can estimate with certainty that a certain number of holes will 

 go off at each operation. 



An Electric Boat on the Housatonic. 



A bOAT propelled by electricity was first launched Sept. 20 by 

 George G. Grower, electrician and chemist, of Ansonia. Conn.; and 

 about 4 P.M., Monday, Sept. 23, a party, consisting of Mr. Grower, 

 Frank A. Kirkham, and Fred Wehrle. of Ansonia, and a report- 

 er, stepped into the boat and pushed off. 



There is nothing unusual in the appearance of the boat, except a 

 long, box-like structure extending the length of the boat over the 

 keel. When the party was seated, and Mr. Grower pressed a little 

 lever, the boat started up the river at a good rate of speed, although 

 stemming a strong current, as the tide was running out. 



The boat is an ordinary-sized row-boat, fourteen feet in length, 

 and four feet wide. The structure in the centre contains the 

 _storage-battery, of fifty cells, which furnishes the power. A Ferret 



that can be heard is a slight one from the gear, the little vessel 

 gliding along as smoothly as an ocean steamer. Electric lights 

 could easily be arranged, the power of the batteries being calcu- 

 lated for the purpose. 



Many persons watched the craft from the shore, and they had 

 good reason to be puzzled. The picture of a number of persons in 

 a boat, no one being occupied except the pilot, with no oars, sails, 

 or even a smoke-stack visible, and with the boat rushing through 

 the water, would naturally excite the curiosity of the uniniti- 

 ated. 



The trip made Monday was the third one, and on no occasion 

 has there been the slightest hitch or cause for discouragement. 

 The Ferret motor, which is used, is a light one, weighing but ninety 

 pounds, but is of one horse-power, and is of 100 volts electro- 

 motive force. It is very simply managed, all four of the party 

 Monday taking a turn as " engmeer," with equal success. It can 

 be reversed quickly, and stopped instantly. It is biidt so that in 

 starting the power is applied gradually to the motor, thus obviat- 

 ing the danger of burning out the armature. 



Mr. Grower is now introducing the Ferret motors into factories, 

 where power is lost by the large quantity of shafting required. 

 Several of the motors scattered through a factory do away with a 

 lot of the shafting, and save a large proportion of the power which 

 is otherwise lost. 



