10 



KNOWLEDGE & SCIENTIFIC NEWS. 



[January, 1907. 



(2) For the Year. — Cast out the sevens from the last 

 two figures of the year and add the quotient of the 

 same fiijures divided by four, nci^locting fraclions. 

 Thus, for i860, the number is 4 + 15 = 19. o''- ^'asling 

 out the sevens, 5. For 1906 it is o, for i8^o it is 

 5 + 10, or, casting out the sevens, i. 



(3) For the Month Nuinbeis. — These must be 

 memorised ;is follows: — 



r*"or leap years, januaiy is o, l'"el3ruary ,^, llu- others 

 being unaltered. 



(4) For the Day Number. — This is simply the num- 

 ber of the day of the month, casting out the sevens if 

 neoe.ssary. Thus, the 3rd is 3, the J^tli is 4, the 31st 

 is 3, and the j8th is o. 



Fxamples of the application of these rules : — ■ 

 Given such a date as .April 15, i860. 

 The century number is ... 2 

 The year number is ... ... 5 



Casting out tiie .sevens ... ... o 



The month number is ... ... o 



The day number (casting out 7's) i 



Total ... I 

 The day is, therefore, .Sunday. 



Januar\' 13, 1904. 



Century number ... o 



Year number ... ... 5 



Month number (leap year) o 



Day number, 13 (casting • , 



out the sevens) ... 1 



Total ... II or casting out the 

 .sevens, 4. 

 The day is, therefore, Wednesday. 



VVhen the process is carried out mentally, it will 

 be immediately seen in practice that the casting out 

 the sevens as the addition proceeds, does not encumber, 

 but simplifies the operation, as it reduces the addition 

 to small numbers, and the calculation is soon per- 

 formed with surprising rapidity. 



\\'ith regard to leap year, it must be borne in mind 

 that at the even centuries there is no leap year unless 

 divisible by 400. Thus, 1900 is not leap year, nor 1800, 

 but 2000 is. 



THE SUGGESTED BOOK CLUB. 



So very few applications ha\e been received for mem- 

 Ijership of the proposed Scientific Book Club, that we 

 much regret to say it will be impossible to proceed with 

 It. Had only a few hundred applied we might have 

 started the library, even at a loss, but, as "it is, the 

 numbers are such as to show that there is practically no 

 demand for such an institution. The books alreadv 

 purcha.sed will be sold off, and a priced list of them wi'l 

 appear in our next issue. 



White Ants. 



Bv F. H. ScAMMEi.i., F.C.I.S. 



riiiiki-; has Inin considerable diversity of opinion as to 

 what distinct family the insects commonly known as 

 White Ants, otherwise Termites, belong. In some re- 

 spects thev restinble one of the principal insect divi- 

 sions, and in other respects a second. Recently, how- 

 ever, they have been placed by some authorities by 

 themselves in an order known as " Isoptera." The 

 name " White Ants " is somewhat misleading and in- 

 correct, for they differ widely from true ants, and only 

 in some cases are they white. At present there are some 

 300 distinct species known to entomologists, though 

 there are probably many more. They are found only 

 in warm climates, and, with very few exceptions, are 

 entirely vegetarian in their diet. The basis of their 

 food is wo<Kly matter. Certain varieties, however, 

 cultivate, in their termitaria or nests, a peculiar form 

 of fungus upon which they feed; others for the same 

 purpose cut and store up grasses. Termites are par- 

 ticularly cleanly, and consume their dead and any other 

 objectionahle matter which is in their way. They also 

 themselves prepare a peculiar kind of food, of earth, 

 grass, and a salivic deposit from their own bodies. 

 Their chief diet, however, is wood. They usually pre- 

 fer soft woods such as European deal, but there is 

 scarcely any wood which can be regarded as entirely 

 proof against their voracity. Even the well-known 

 West Australian jarrah is attacked by them, although 

 they prefer other kinds of timber. It may be here noted 

 that the comparative immunity jarrah enjoys largely 

 depends upon the ground upon which it is grown, that 

 grown in the ironstone ranges being more immune 

 than the same wood from other parts of the State. 



Termites are gregarious insects. They live in fami- 

 lies or colonies and appear to be governed by laws and 

 to work systematically. Different varieties construct 

 totally ditTerent kinds of dwellings. Some take up their 

 abode in trunks of trees, while others construct mounds, 

 rising in some cases as high as 18 feet, a third variety 

 dwelling in subterranean passages, burrowed in the 

 ground, or simply living in decayed pieces of wood. 

 The number of individuals in a colony may run from a 

 few hundreds to hundreds of thousands. In most 

 varieties the inhabitants of a colony are usually confined 

 to the offspring of one Royal pair, although in nearly 

 all nests there are to be found complementary and sup- 

 plementary royal individuals. Unlike other social 

 insects vvfiere there is a marked difference between the 

 males and females, and where the workers are of the 

 female sex, as is the case in bees, in Termites the males 

 and females are closely similar, and. the castes are in no 

 way correlative with sex. The following kinds of 

 adults are usually present in a colony, viz : — 



1. Workers. 



2. .Soldiers. 



3. Winged individuals, known as imagos or 

 nymphs, ready to leave the nest. 



4. King and Queen. 



5. Complementary and .Supplementary Royal in- 

 dividuals. 



These, according to their relative condition of de- 

 velopment, may be further divided until as many as 

 eleven or more distinct varieties are found in one colony. 



The workers, which are usually blind, have no trace 

 of wings except in some instances where there are 

 slight stumps. As their name indicates, they are 

 generally the food-winners, and their duties comprise the 



