May 9, 1919] 



SCIENCE 



451 



large tubes of pjTex glass. Small tubes, up to 

 about 20 mm. in diameter, yield readily to the 

 usual file mark. 



A well-lcnown method for cutting large tubes 

 of common glass is to make a file scratch 

 round the tube, apply one turn of an iron wire 

 held taut, and then heat the same to redness 

 by an electric current. 



This method, however, -without modification, 

 fails when attempting to cut pyrex tubes. 

 The glass will simply not crack, and if the 

 heating is pushed the hot wire usually sinks 

 into the glass and finally fuses imder the 

 intense heat. 



I was surprised recently to find that if the 

 iron wire is replaced by a niehrome wire, say, 

 of no. 14 or 16 gauge, the tube may be cut off 

 by the incandescent wire in the same maimer 

 that a cake of soap is cut in two parts by 

 means of a string. 



To insure success proceed as follows: Take 

 a length of about one foot of niehrome 

 wire, connect it up to a D. C. (or A. C.) dy- 

 namo current and include an adjustable tin 

 resistance (for the current required must nec- 

 essarily be large). The wire is held under 

 tension by pulling on it with a pair of pincers, 

 as shown in Fig. 1. Care must be taken not 

 to let the two parts of the wire touch at A. 



When all is in readiness, turn on the heating 

 current and adjust same by means of the tin 

 resistance until the wire glows a white heat. 

 If now a blast from a hand torch be allowed 

 to play on the wire and glass the tube may be 

 cut as shown in Fig. 2. Be careful not to let 

 the flame strike the glowing wire where it 

 is not in contact with the glass for the extra 

 heat will burn it. The object of the blast is 

 to aid in softening the glass, and also to dis- 

 tribute the heat along the tube and thus pre- 

 vent the freshly cut edges from checking due 

 to the otherwise intense local heating. The 

 burr of glass that results from the cutting 

 may be removed by a file or on the grindstone. 



Recently the neck of a twelve-liter pyrex 

 Florence flask was cut off with the greatest 

 ease. The diameter was about 60 ram., and 

 the wall thickness about 2.5 mm. 



Chas. T. Knipp 



Universitt of Illinois 



THE ILLINOIS STATE ACADEMY OF 

 SCIENCE 



The twelfth annual meeting of the Illinois State 

 Academy of Science was held at Jacksonville, 111., 

 on March 21 and 22, having been postponed a 

 month on account of the prevalence of influenza. 



Important items of business transacted were the 

 following: It was voted that the academy become 

 affiliated with the American Association for the 

 Advancement of Science, on the plan proposed by 

 the committee on affiliations, of the American 

 Association. It was voted that the academy be- 

 come affiliated with the Division of State Museum 

 of the Department of Registration and Education 

 of the State Government. It was voted that the 

 academy seek affiliated relations with science clubs 

 in high schools, colleges and elsewhere in the state 

 and a committee was appointed to perfect a plan 

 for such affiliations. A committee on secondary- 

 school science instruction was appointed. This 

 committee is to make annual reports to the acad- 

 emy and to ask the aid and cooperation of the 

 academy in its efforts to further the interests of 

 such instruction. It was voted to offer for sale to 

 libraries and individuals, full sets of the ten vol- 

 umes of transactions now published at $5 per set. 



Through the affiliated relation of the academy 

 with the state museum, the former is practically 

 guaranteed financial ai<l from the state for the 



