462 SCIENCE PROGRESS 



i8. Fermentation Chemistry includes the brewing and malting of 

 beverages, vinegars, the manufacture of industrial alcohol, yeast, and 

 certain colouring matters. 



19. Agricultural Chemistry, in its narrow sense, deals with the 

 chemistry of soils, fertilisers, manures, etc., and has as its purpose the 

 improvement of land values and the increase of crops. 



The indirect application of chemistry includes the many branches of 

 industrial and manufacturing chemistry as well as its use in professions, 

 trades, and arts. They may be grouped in various ways, either as to the 

 source of the raw material {e.g. of vegetable, animal, or mineral source), 

 or the respective industries, or the respective purposes. The following is 

 an attempt to combine some of these factors. 



■20. Technical Chemistry, or the application in technic, e.g. (a) photo- 

 graphical (not photo-chemistry) ; {b) pyrotechnical (explosives, matches, 

 fireworks) ; (c) ceramical (pottery, vases, and their metallic colours) ; {d) 

 laundering (cleaning, bleaching, washing, and starching). 



21. Industrial Chemistry, or the application in industry, e.g. {a) 

 textile (fabrics and dyes) ; (&) leather (tanning materials) ; (c) paper (fibres, 

 cellulose, etc.) ; {d) rubber and allied substances. 



22. Engineering Chemistry, or the application in engineering, e.g. {a) 

 metallurgy (iron, steel, alloys, and heavy metals) ; [b) building materials 

 (cement, mortar, lime-bricks) ; (c) fuel (gas, tar, coke, petroleum, asphalts) . 



23. Commercial Chemistry, or the application in commerce, e.g. 

 {a) perfumery (essential oils, flavouring materials, fruit essences) ; (6) soaps, 

 washing powders, candles ; (c) paints, inks, stains ; {d) varnishes and shellacs, 

 etc. 



24. Manufacturing Chemistry, or the manufacture from raw materials: 

 (a) acids, alkalies, and salts ; (b) fats, oils, and waxes ; (c) silicates (glass 

 and porcelain) ; {d) carbohydrates (sugars, dextrin, starch, etc.) ; {e) proteins 

 (casein, ferments, etc.) ; (/) resins (gums, oleo-resins, agar-agar) ; {g) glue 

 and gelatine. 



The classification outlined above is merely an attempt at a logical and 

 uniform classification which enables a clearer definition of certain chemical 

 branches. For instance: photo-chemistry and photographical chemistry 

 are distinctly different, yet some dictionaries consider them synonymous. 

 The enumeration of the many branches is also an index of the extensive 

 proportion which chemical knowledge has acquired in human affairs. 



"UNOFFICIAL" MOSQUITO CONTB.OL IN ENGLAND (John 

 F. Marshall, M.A.). 



" So far as my experience goes, it has been demonstrated that mosquitoes 

 can be as completely exterminated in any locality as dirt can be swept from 

 a building or as weeds from a walk, . . . and with the exercise of no more intelli- 

 gence and much less labour than is required in the performance of many domestic 

 duties. My experience would lead me to conclude that, if mosquitoes continue to 

 exist in any locality, it is because the people are too indifferent to the annoyance 

 to take the trouble to be rid of it.'" — Extract from a speech delivered by Mr. 

 W. J. Matheson at the First Anti-Mosquito Convention in New York, Decem- 

 ber 16, 1903. 



As most people nowadays are aware, a mosquito, or " gnat," is a two-winged 

 fly, easily recognised by its long " beak," or " proboscis." This proboscis 

 is actually a sheath containing a formidable collection of pointed instruments, 

 with which the female mosquito pierces the skin of men and animals, and 

 rapidly sucks their blood. 



Mosquitoes were not really taken seriously until the year 1897, when Ross 



