242 



♦ KNO\VLEDGE 



[Oct. 19, 1883. 



; LAMES.* 



By W. Mattieu Williams. 



■\"Tty"HAT are they 1 They are commonly described as 

 VV merely heated or " incandescent " gas. In a note 

 to Chapter VII. of " The Fuel of the Sun " I stated some 

 reasons for questioning this definition and justifying "the 

 conclusion that Hame should be classed as another and dis- 

 tinct form of matter, in addition to those of the solid, 

 liquid, and gaseous forms ; " thus reverting to the four 

 elements of the ancients — fire, air, earth, and water — their 

 real meaning being that matter existed in one or other of 

 the four conditions of fire, gas, solid, or liquid, their use of 

 the word "element " being to express the idea that we now 

 represent by " state." 



I suggested further investigation of the difference 

 between flame and incandescent gases, and Dr. W. Siemens 

 has recently used the opportunities aflbrded by his rege- 

 nerative glass furnaces for making such investigations. He 

 finds that gases are not luminous at the temperature of 

 molten steel (1,-500° to 2,000° C). At this high tempera- 

 ture the air emitted no light to a darkened room, showing 

 that gases cannot be made red-hot or white-hot as solids 

 may. 



Further observations on the behaviour of flames them- 

 selves disproved Davy's theory that their luminosity is due 

 to the incandescence of precipitated particles of carbon or 

 other solids. My experiments showing the transparency 

 of luminous flames (described in the above-quoted chapter) 

 led me to the same conclusion, as such transparency of the 

 white portion of the flame would be impossible if it were 

 loaded with solid particles of carbon packed so closely 

 together as to display continuous luminosity by their 

 incandescence. 



In the German Annalen of Chemistry and Physics, W. 

 Hittorf now claims priority over Siemens in respect to 

 demonstrating this non-luminosity of heated gases. He 

 observed in 1879 that a layer of air surrounding electrodes 

 of platinum, made white-hot by a battoi-y of 1,600 celLs, 

 appeared perfectl}' dark, and that with iridium heated even 

 up to fusion by a battery of 2,400 elements, the gas media 

 whether nitrogen, hydrogen, or oxygen, remained perfectly 

 dark, and that these gases, when thus heated, became good 

 conductors of electricity, even when its potentiality or 

 penetrating power was low. 



It appears that Wedgwood in 1792 made similar furnace 

 observations to those of Siemens, and, like him, concluded 

 that the heated air therein was not luminous. 



It appears, therefore, that flame is not white-hot gas, 

 nor white-hot solid particles precipitated from the gas, but 

 is matter in a fourth condition — i.e., in the act of vigorous 

 combination, or what I will venture to call chemical vitalifi/. 

 Animal and vegetable activities depend upon the 

 chemical combinations proceeding in organic structures, 

 and if we may apply to the sum of these activities the 

 designation of vegetable and animal life, I am justified in 

 describing flames as an intense manifestation of inorganic 

 or mineral life. There is really no innovation in this, but 

 the opposite ; it is a return to some very ancient con- 

 ceptions. 



In excavating at Suresnes, at the extremity of the Bois 

 de Boulogne, the remains of a lake, or rather river, 

 dwelling have been found. They consist, according to a 

 correspondent of the Jiappd, of piles and an enormous 

 quantity and variety of bones, but at present no trace of 

 iron or bronze has been discovered. 



* From the Cfentleman's Magazine. 



PLEASANT HOUES WITH THE 

 MICROSCOPE. 



By Henry J. Slack, F.G.S., F.R.M.S. 



THE sketches of the mouth organs of the honey-bee 

 given in Knowledge, October 5, show that the insect 

 is provided with a licking, lapping, and sucking tongue of 

 considerable length, while the wasp family have very much 

 shorter tongues, and, except by biting a hole in tubular 

 flowers, would not get at the nectar which the bee's tongue, 

 like the long proboscis of the butterfly, makes it easy to 

 reach. 



Various accounts are given in different books of the 

 structure of the bee's tongue, and some of them are evi- 

 dently founded upon imperfect observation. Such objects 

 are by no means easy to see properly, and as many readers 

 of Knowledge may be glad of a little help in making a 

 microscopical examination, we may suggest how they had 

 better proceed. First catch a bee, as directed in the last 

 paper, and watch it feeding in the test-tube. As stated, 

 the tongue makes a sweeping, backhanded motion. It is 

 like putting the hand, knuckles all down, on the table, and 

 then drawing it forwards, raising it a little, and finishing 

 the sweeping motion at the finger-tips. To understand the 

 meaning of these motions, cut off the head of a bee, stretch 

 the tongue out with a needle stuck in a little wooden 

 handle, and then with a droplet of gum fix the head on to 

 a glass slide. These arrangements and ordinary dissections 

 are easily made under a hand -magnifier, the object being 

 placed on a piece of glass. Mr. Baker (High Holborn) 

 sells hand-magnifiers for the pocket, which can also be 

 attached to little brass stands to hold them,' at any height 

 required, and they are good substitutes for a dissecting 

 microscope. Mr. Browning also makes a cheap botanical 

 dissecting microscope, which, with a larger piece of glass 

 for a stage, answers for general purposes. 



Having prepared a bee's head as described, look at it 

 with an inch power and reflected light. This enables it to 

 be seen much as is represented in Fig. 1 in the last article, 

 but the tip will, if the specimen is quite fresh and un- 

 injured, look a little rounder. The mandibles, D D, are 

 depressed in the figure to show the other parts better. 

 After carefully looking at the bee's head in the way men- 

 tioned, take another bee and carefully remove all the 

 mouth organs from the head, operating with needles, while 

 the object, or subject, is immersed in a drop or two 

 of glycerine. This fluid prevents any shrinking of the 

 parts, and gradually sinks in, making them transparent. 

 As soon as the mouth organs have been well cleaned 

 from any dirt or stray particles, place them in the 

 little cavity of a " hollow glass slide " which opticians 

 sell. 



This is an ordinary slide of thin plate-glass with a 

 hollow ground out in the middle, and then polished. 

 It forms a convenient cell in which to examine objects 

 that must not be squeezed flat. In the case of the 

 bee's mouth organs it is well to remove the mandibles, as 

 they are in the way of seeing other parts. The hollow 

 slide should be filled with glycerine diluted with a little 

 water, and the tongue, labial palpi, and maxilla; neatly 

 spread out. Then put on a glass cover. This most likely 

 squeezes some of the fluid out, although the precaution has 

 been taken of putting a drop of glycerine upon it before 

 placing it over the object. If an inconveniently large 

 air bubble is formed, slide the cover a little off the 

 hollow, and put in a little more water or glycerine 

 with a glass tube drawn out like a dropping tube, 

 but with a rather finer point than usual. When 



