220 SEC. 8. HEAT. 



997. A Gas Lamp, consisting of four Bunsen burners, and 

 provided with an air-regulating system. 



S. Hoogewerff, Dr. Phil., at Rotterdam. 



This lamp, which is intended for heating tubes, was constructed by 

 Mr. Verkerck, mechanical engineer, at Utrecht, under the directions of 

 Dr. Hoogewerff, and belongs to the middle school at Rotterdam. 



998. A Gas Lamp (Bunsen's system), intended for heating 

 porcelain vessels of large size. 



S. Hoogewerff, Dr. Phil., at Rotterdam. 



It was constructed, under the directions of Dr. Hoogewerff, by Mr. Verkerck, 

 mechanical engineer, at Utrecht, and belongs to the middle school at 

 Rotterdam. 



999. Apparatus for showing the liberation of heat during 

 solidification. Will. Haak, Neuhaus am Rennweg, Thuringen. 



II. THERMOMETRY AND PYROMETRY. 



1000. Thermometer. " The Great Pyramid temperature 

 scale, and its standard reference point of 50 P." With a map of 

 the world to illustrate the advantages of this standard. 



Prof. Piazzi Smyth, Royal Observatory, Edinburgh. 



This consists of a large table thermometer, graduated according to the in- 

 dications of the Great Pyramid system of standards ; firstly, by colours into 

 fifths of the distance between freezing and boiling of water, and then each 

 fifth into 50, or 250 for the whole distance. 



A map of the world on an equal-surface projection accompanies the 

 thermometer, and exhibits the mean temperature of the whole earth's surface 

 according to the Great Pyramid scale ; illustrating also the territorial and in- 

 ternational advantages to all civilised nations of adopting the mean tempera- 

 ture standard of the Great Pyramid, viz., 50 Pyr. or 68 Fahr., as the tem- 

 perature reference standard for all human purposes, scientific, social, and 

 commercial. 



1001. Legible Spirit Thermometers, with line at above 

 and below the proper temperature of a room, so that the degree 

 can be read off at a long distance, at the opposite side of a large 

 room, or at the ceiling, for experiments in ventilation. 



Peter Hinckes Bird, F.R.C.S. Lond. 



1002. Apparatus for determining the Boiling Point of a 

 small quantity of Fluid. 



The Secondary Government School, Assen (Netherlands). 

 In this simple apparatus, constructed after the design of Dr. A. Van Hasselt, 

 (teacher at school for middle-class education at Assen), the little tube is filled 

 for the greater part with mercury ; the remaining space with the fluid. The 

 tube is then turned upside down into a small beaker-jar, which is also filled 

 with mercury ; part of this must be removed until the quantity left rises about 



